Adenovirus comprising an albumin-binding moiety

ABSTRACT

The invention relates to a recombinant adenovirus comprising an albumin-binding moiety on the outer surface of the adenoviral hexon protein, pharmaceutical compositions containing it and its medical use. Particularly, the invention relates to an oncolytic adenovirus comprising a sequence encoding an albumin-binding moiety inserted in the hypervariable region 1 (HVR1) of the hexon protein coding sequence and its use in the prevention and/or treatment of cancer.

CROSS-REFERENCE TO RELATED APPLICATIONS

This is a continuation under 35 USC § 120 of U.S. patent applicationSer. No. 15/307,408 filed Oct. 28, 2016 in the names of RAMON ALEMANYBONASTRE and LUIS ALFONSO ROJAS EXPÓSITO for ADENOVIRUS COMPRISING ANALBUMIN-BINDING MOIETY, which in turn is a U.S. national phaseapplication under the provisions of 35 U.S.C. § 371 of InternationalPatent Application No. PCT/EP15/59593 filed Apr. 30, 2015, which in turnclaims priority of European Patent Application No. 14382162.7 filed Apr.30, 2014. The disclosures of U.S. patent application Ser. No.15/307,408, International Patent Application No. PCT/EP15/59593 andEuropean Patent Application No. 14382162.7 are hereby incorporatedherein by reference in their respective entireties, for all purposes.

DESCRIPTION OF THE TEXT FILE SUBMITTED ELECTRONICALLY

The content of the text file submitted electronically herewith isincorporated herein by reference in its entirety: A computer readableformat copy of the Sequence Listing (Filename:“VCN-003C1_Replacement_Sequence_Listing.txt”; Date created: Aug. 10,2022; File size: 21.7 KB).

FIELD OF THE INVENTION

The invention relates to the field of disease therapy and, more inparticular, to a recombinant adenovirus for gene therapy or virotherapycomprising an albumin-binding moiety on the outer surface of theadenoviral hexon protein, particularly to an oncolytic adenoviruscomprising an albumin-binding moiety and to its use for the preventionand/or treatment of cancer. Said adenoviruses are shielded againstneutralizing antibodies present in the bloodstream and are thusparticularly suitable for systemic administration.

BACKGROUND OF THE INVENTION

Adenoviruses have been extensively used as gene delivery vectors forgene therapy as well as oncolytic agents for cancer treatment. Theyexhibit several features that make them suitable for these applications.Namely, their structure and biology has been widely studied which allowsfor an easy modification of their genome, they are able to infect bothreplicating and non-replicating cells, and they can easily be producedat high titers for their use in the clinic. In terms of safety, they donot cause life-threatening diseases in humans, and their genome isnon-integrative which prevents for insertional mutagenesis. Clinicaltrials with adenovirus-based vectors report a good toxicology and safetyprofile, although the efficacy still needs improvement, especially whenthe virus is administered systemically.

In the field of gene therapy, systemic administration, that is,injection into the bloodstream endovenously or intra-arterially, may beneeded to reach multiple organs or disseminated cells. For example, incancer therapy with adenovirus vectors and oncolytic adenovirusessystemic administration is necessary to treat disseminated tumours at anadvanced or metastatic stage. Nonetheless, adenoviruses show importantlimitations when injected into the bloodstream that impair the efficacyof the therapy. Adenovirus type 5 (Ad5) suffers multiple neutralizinginteractions in the bloodstream that reduce drastically thebioavailability of the virus. Liver sequestration represents the majorobstacle for the therapy since >90% of the injected dose is retained bythis organ, mainly by liver macrophages named Kupffer cells, but also byliver sinusoidal endothelial cells (LSECs) and hepatocytes. Directinteraction with blood cells and proteins also represents an importantbarrier. Ad5 can bind directly to blood cells such as erythrocytes viaCAR receptor and to platelets via integrins. Antibodies not only canneutralize the virus directly but can also trigger an innate immuneresponse by complement activation and by docking the virus particles tothe Fc receptors of monocytes and neutrophils. Furthermore, vectorre-administration raises the levels of anti-Ad neutralizing antibodies(NAbs) and therefore the neutralization of the virus. Adenovirusopsonization by antibodies and complement also enhances clearance byKupffer cells. Altogether, these interactions result in a very shorthalf-life of Ad in blood, of about few minutes in mice and humans.

Extensive efforts have been made to evade the neutralization byantibodies and immune cells when the adenovirus is systemicallyadministered.

Chemical modification of adenovirus capsid with polymers(polyethyleneglycol (PEG) or N-(2-hydroxypropyl)methacrylamide (HPMA))has been tested. Polymer conjugation on viral surface enabled the virusto evade neutralisation by antibodies and immune cells as well asablates CAR, integrin, and FX-binding. Nevertheless, polymers conjugatedto the capsid do not pass to the virus progeny and increase thecomplexity of large-scale GMP production for clinical application.

WO 2011/129468 A9 discloses a chimeric adenovirus capable of evadingimmune recognition of neutralizing antibodies. Said adenovirus wasobtained by genetic modification of the capsid of human adenovirusserotype 5, wherein the gene that codes for hexon protein was replacedby the hexon gene from simian adenovirus serotype 19. The chimericadenovirus obtained showed also higher anti-tumour activity than thesame adenovirus without the genetic modification.

Several attempts have been made in order to obtain an adenovirusshielded by albumin protein (see WO 2007/050128 A2). However,experimental evidence has demonstrated that an adenovirus having acapsid modified with an albumin-binding domain is not protected againstneutralizing antibodies (Hedley S. J. et al. 2009. The Open Gene TherapyJournal, 2:1-11).

Therefore, there is still a need for further genetic modified adenovirussuitable for systemic administration and capable of escapingneutralizing antibodies.

BRIEF DESCRIPTION OF THE INVENTION

In a first aspect, the invention relates to an adenoviral genomecharacterized in that it comprises a sequence encoding analbumin-binding moiety inserted in the coding region of thehypervariable region 1 (HVR1) of the hexon protein which results in theexpression of fusion protein comprising a hexon protein and analbumin-binding moiety and wherein the albumin-binding moiety is locatedon the outer surface of the hexon protein when the hexon protein isassembled in the adenovirus capsid.

In a second aspect, the invention relates to a recombinant adenovirushaving an adenoviral genome according to the invention.

In a third aspect, the invention relates to a pharmaceutical compositioncomprising a therapeutically effective amount of a recombinantadenovirus according to the invention together with a pharmaceuticallyacceptable carrier.

In a fourth aspect, the invention relates to a recombinant adenovirus ora pharmaceutical composition according to the invention for use inmedicine.

In a further aspect, the invention relates to a recombinant adenovirusor a pharmaceutical composition according to the invention for use inthe prevention and/or treatment of cancer in a mammal, wherein theadenovirus is an oncolytic adenovirus or an adenovirus comprising a geneused in cancer therapy inserted in its genome.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 . Schematic diagram of albumin-binding domain (ABD) insertion inICOVIR15-ABD. The ABD 3 from streptococcal protein G (SEQ ID NO: 1) isflanked by two GSGS (SEQ ID NO: 2) linkers and inserted in the middle ofthe hypervariable region 1 (HVR1) of hexon of oncolytic adenovirusICOVIR15 obtaining ICOVIR15-ABD. LITR/RITR, left and right invertedterminal repeats; MLP, major late promoter; E1Ap, modified E1A promoter;E1A-Δ24, mutant version of E1A protein where amino acids 121-129 of thepolypeptide chain have been deleted; L1 to L5, late genes; Fiber RGD,RGD-modified fiber by insertion of the RGD peptide at the H1l-loop ofthe fiber.

FIG. 2 . Drawing of an adenovirus containing an albumin binding domain(ABD) inserted in the hexon. Compared to a non-modified adenovirusICOVIR15 (left), the ABD-modified virus ICOVIR-15-ABD (right) is coatedwith albumin present in blood, shielding the virus from neutralizingantibodies.

FIG. 3 . Viral production kinetics of ICOVIR15-ABD and ICOVIR15.Confluent A549 cells were infected with 800 viral particles (vp) percell. Four hours (h) after the infection the virus was removed, cellswere washed thrice with PBS and incubated with virus-free medium. Cellextracts were collected 4, 24, 48, and 72 hours after the infection andtitrated by antihexon staining-based method. Samples were evaluated intriplicate. Mean±SD error bars are plotted (although these are difficultto distinguish because their low values). TU/mL, transducing units permL. * Statistical significance compared to ICOVIR15 group (p≤0.05).

FIG. 4 . Comparative cytotoxicity in vitro of ICOVIR15 and ICOVIR15-ABDin presence or absence of human serum albumin (HSA). A549, Sk-mel28,HEK293 and MCF-7 cells were infected with the indicated viruses from10000 to 0.0001 viral particles (vp) per cell. IC50 values (vp per cellrequired to cause a reduction of 50% in cell culture viability) at day 7after infection are shown. Three different replicates were quantifiedfor each cell line. Mean±SD error bars are plotted. MOI, multiplicity ofinfection.

FIGS. 5A and 5B. ICOVIR15-ABD binds human and mouse albumin as detectedby ELISA. FIG. 5A) Wells were coated with either human or bovine serumalbumin (HSA or BSA, which binds or doesn't bind to ABD, respectively).Three different amounts of viral protein were tested to detect thebinding (0.25, 2.5, and 25 ng). ICOVIR15 and ICOVIR15-ABD adenovirusesbinding to albumin-coated wells were detected after incubation withantihexon antibody and peroxidase-labelled secondary antibody bycolorimetric analysis. Samples were evaluated in triplicate. Mean±SDerror bars are plotted. OD, optical density. * Statistical significancecompared to other groups (p≤0.05). FIG. 5B) Wells were coated witheither bovine, human, or mouse serum albumin (BSA, HSA, or MSA). Theamount of viral protein tested was 25 ng. Adenovirus binding toalbumin-coated wells was detected after incubation with antihexonantibody and peroxidase-labelled secondary antibody by colorimetricanalysis. A control mock group without adenovirus was included. Sampleswere evaluated in triplicate. Mean±SD error bars are plotted. OD,optical density. * Statistical significance compared to other groups(p≤0.05).

FIG. 6 . Albumin-binding protects adenovirus from neutralizingantibodies in vitro. AdGL and AdGL-ABD adenoviruses coated or not withhuman serum albumin (HSA) were incubated with serial dilutions of theneutralizing antibody Ab6982 for 1 hour at 37° C. HEK293 cells were thenadded to obtain a multiplicity of infection of 0.5 transducing units(TU) per cell. 24 hours after the infection, transduction of cells wasanalyzed by luciferase expression. A control without antibody (Ab) (“noAb” control) was included to obtain the 100% infection value. Sampleswere evaluated in triplicate. Mean±SD error bars are plotted.

FIG. 7 . ICOVIR15-ABD shows an increased in vitro cytotoxicity inpresence of neutralizing antibodies when protected with human serumalbumin (HSA). ICOVIR15 and ICOVIR15-ABD were incubated with serialdilutions of the neutralizing antibody Ab6982 (Nab, commercialpolyclonal anti-HAd5) for 1 hour in presence or absence of Human SerumAlbumin (HSA). A549 cells were added to obtain a multiplicity ofinfection of 600 viral particles (vp) per cell. The percentage ofsurviving cells (protein content in the wells) was measured at day 4post-infection. Samples were evaluated in triplicate. Mean±SD error barsare plotted.

FIG. 8 . ABD insertion increases the adenovirus plasma half-life. Nudemice were injected with a mixture of ICOVIR15 and ICOVIR15-ABD at aratio 1:1 with a total dose of 5×10¹⁰ viral particles (vp) per mouse(n=5). Blood samples were collected 5, 15 min, 1, 4, and 24 hours afteradministration and centrifuged to collect the serum. PCR amplificationof the hypervariable region 1 (HVR1) of adenovirus hexon was performedand samples were analyzed by electrophoresis. The ABD insertionincreases the size of the HVR1 from 299 to 361 bp. The gel shows astandard with several ratios of ICOVIR15-ABD: ICOVIR15 genomes (0.2, 1,5, 10 and 50), a pre-injection control (to), a water negative-control ofthe PCR (H₂O), and the PCR of the serum samples (#1 to #5).

FIG. 9 . Anti-tumour activity of ICOVIR15-ABD after systemicadministration in vivo. Nude mice bearing subcutaneous xenografts ofmelanoma (Sk-mel28) were injected with a single intravenous dose ofphosphate-buffered saline (PBS), ICOVIR15 or ICOVIR15-ABD (5×10¹⁰ viralparticles (vp) per mouse). Tumour volumes±SEM are plotted (n=10-12). *Statistical significance compared to PBS group (p≤0.05).

FIG. 10 . In vivo liver and tumor transduction with an adenoviral vectormodified with an albumin binding domain in the hexon HVR1 is preservedin adenovirus-preimmune mice. C57BL/6 mice bearing subcutaneousxenografts of melanoma (B16-CAR) were immunized with an intraperitonealinjection of hAd5wt (2×10¹⁰ viral particles (vp) per mouse) or vehicle,and 7 days later were injected intravenously with AdGL (GFP-Luciferasevector) or AdGL-ABD (3×10¹⁰ vp per mouse). Three days later luciferaseactivity in liver and tumor was analyzed by bioluminescence imaging(IVIS). Mean±SEM are plotted (livers n=4-6, tumors n=8-12). sec:seconds; sr: steradian.

FIG. 11 . ABD insertion in hypervariable-region 5 does not affect thevirus viability. HEK293 cells were transfected with pAdZGL-H5-ABDplasmid to generate AdGL-H5-ABD virus. After one week the cells andsupernatant were harvested and lysed by three freeze-thaw cycles. Thecell extract containing virus was tittered in HEK293 cells by plaqueassay. Wells corresponding to dilutions 1E6, 1E7 and 1E8 are shown,where plaques demonstrating virus propagation are evident.

FIG. 12 . Albumin-binding domain inserted in HVR5 does not protectadenovirus from neutralizing antibodies, contrary to the same domaininserted in HVR1. An in vitro neutralization experiment was performed inHEK293 and Sk-mel28 cells comparing AdGL, AdGL-H1-ABD, and AdGL-H5-ABD.Adenoviruses were incubated for 1 hour with serial dilutions of theneutralizing antibody Ab6982 in presence or absence of Human SerumAlbumin (HSA). Cells were subsequently added to obtain a multiplicity ofinfection of 10 viral particles (vp) per cell (HEK293) and 40 vp percell (Sk-mel28). Twenty-four hours after the infection, transduction ofcells was analyzed by luciferase expression. A control without antibody(Ab) (“no Ab” control) was included to obtain the 100% infection valueSamples were evaluated in triplicate. Mean±SD error bars are plotted.

DETAILED DESCRIPTION OF THE INVENTION

The inventors of the present invention have discovered that anadenovirus genetically modified with an albumin-binding moiety on theouter surface of the capsid, particularly on the outer surface of theadenoviral hexon protein, is capable of acquiring an albumin shieldallowing the virus to escape neutralizing antibodies and increasing itsblood persistence after systemic administration. This result isunexpected because previous attempts of modifying an adenovirus with analbumin-binding domain failed to increase protection of the adenovirusagainst neutralizing antibodies (Hedley S. J. et al. 2009. The Open GeneTherapy Journal, 2:1-11).

Additionally, when the recombinant adenovirus is an oncolyticadenovirus, the insertion of the albumin-binding moiety improves itsanti-tumour activity. In this sense, said genetically modifiedadenoviruses have potential value for overcoming limitations of systemicadministration, particularly for the treatment of cancer.

The results provided in the examples of the present invention clearlyshow that a replication-selective oncolytic adenovirus (ICOVIR15-ABD)comprising a sequence encoding an albumin-binding domain (ABD) fromstreptococcal protein G inserted in the hypervariable region 1 (HVR1) ofthe hexon protein coding sequence, expose this domain on its capsidpromoting albumin binding, shielding the adenovirus against neutralizingantibodies, increasing its plasma half-life and improving itsanti-tumour efficacy. The experimental examples provided by the presentinvention also show that the insertion of an ABD from streptococcalprotein G in the HVR1 of the hexon protein of a replication-deficientadenovirus (AdGL-ABD) protects the adenovirus from neutralizingantibodies (FIG. 6 ). Thus, these results show that the albumin-coatingof the adenovirus acts as a shield to hide viral proteins and avoidmultiple undesired interactions in blood (neutralizing antibodies,blood-cell absorption and liver uptake) improving its pharmacokinetics.This is especially important when an adenovirus vector for gene therapy,vaccine or oncolytic adenovirus is re-administered. Therefore, thegenetically modified adenoviruses of the invention are suitable forsystemic administration.

Adenoviruses of the Invention

The results obtained in the present invention show that an adenoviruscomprising an albumin-binding moiety on the outer surface of theadenoviral hexon protein can be coated with albumin thus protectingitself from neutralizing antibodies present in the bloodstream. Thisprotective effect is observed both for replicative (ICOVIR15-ABD) andnon-replicative (AdGL-ABD) adenoviruses.

In an aspect, the invention relates to a recombinant adenovirus havingan adenoviral genome characterized in that it comprises a sequenceencoding an albumin-binding moiety inserted in the coding region of thehypervariable region 1 (HVR1) of the hexon protein which results in theexpression of fusion protein comprising a hexon protein and analbumin-binding moiety and wherein the albumin-binding moiety is locatedon the outer surface of the hexon protein when the hexon protein isassembled in the adenovirus capsid.

The term “adenovirus”, as used herein, refers to any virus that can becategorized as an adenovirus, i.e. any virus pertaining to theAdenoviridae family characterized by being a non-enveloped virus with anicosahedral nucleocapsid containing a double stranded DNA genome. Thisterm includes any adenovirus capable of infecting a human or an animal,including all groups, subgroups, and serotypes that use CAR as receptorfor infection of target cells. Adenoviruses of the present inventioninclude, without limitation, avian, canine, equine, bovine, ovine,porcine, human or frog adenovirus. In a preferred embodiment theadenovirus of the invention is a human adenovirus, i.e. an adenoviruscapable of infecting humans. According to the invention, a “serotype” iseach of the immunologically different types of adenovirus. There are atleast 57 serotypes of human adenovirus that are classified into severalsubgroups (A to G). The invention contemplates the use of any adenoviralserotype known in the state of the art including, without limitation,any of the serotypes defined in Table 1.

TABLE 1 Several examples of adenoviral subgroups and serotypes suitablefor use in the present invention. Subgroup Serotypes A 12, 18, 31 B 3,7, 11, 14, 16, 21, 34, 35, 50, 55 C 1, 2, 5, 6, 57 D 8, 9, 10, 13, 15,17, 19, 20, 22-30, 32, 33, 36-39, 42-49, 51, 53, 54, 56 E  4 F 40, 41 G52

In a preferred embodiment, the human adenovirus is selected from thegroup consisting of human adenovirus serotypes 1 to 57.

In another preferred embodiment the adenovirus pertains to subgroup C,more preferably is serotype 5.

Human adenovirus serotype 5 (Ad5) is associated with mild respiratoryinfections. The gene sequence of human adenovirus serotype 5 can befound in GenBank: AY339865.1 (version of 13 Aug. 2007).

The adenovirus of the invention is a recombinant adenovirus. The term“recombinant”, as used herein, refers to an adenovirus that does notappear naturally. This recombinant adenovirus contains one or moremodifications with respect to the wild-type. Such modifications include,but are not limited to, modifications to the adenovirus genome that ispackaged in the particle in order to make an infectious virus. Othermodifications allow obtaining replication-deficient virus (i.e. virusthat cannot reproduce) by removing a gene from the virus genome that iscritical for replication. Exemplary modifications include deletionsknown in the art, such as deletions in one or more of the E1a, E1b, E2a,E2b, E3, or E4 coding regions. Other exemplary modifications includedeletions of all of the coding regions of the adenoviral genome. Suchadenoviruses are known as “gutless” adenoviruses. Chimeric adenovirusesformed by combination of elements from different serotypes are alsoincluded.

The term “recombinant” also includes replication-conditionaladenoviruses, which are viruses that preferentially replicate in certaintypes of cells or tissues but to a lesser degree or not at all in othertypes. For example, among the adenoviruses provided herein, areadenoviruses that replicate in abnormally proliferating tissue, such assolid tumours and other neoplasms. These include the viruses disclosedin U.S. Pat. Nos. 5,998,205 and 5,801,029. Such viruses are sometimesreferred to as “cytolytic” or “cytopathic” viruses (or vectors), and, ifthey have such an effect on neoplastic cells, are referred to as“oncolytic” viruses (or vectors).

In an embodiment the adenovirus is a replicative adenovirus,particularly an oncolytic adenovirus.

In another embodiment the adenovirus is a non-replicative adenovirus ora replication-deficient adenovirus. Replication-deficient adenovirus ornon-replicating adenovirus are adenovirus unable to replicate in thetarget cell that are used in gene therapy as carriers of genes to targetcells since the goal is to express the therapeutic gene within the celland not the lysis of the cell.

The recombinant adenovirus of the present invention is modified byinsertion of a heterologous sequence on the outer surface of theadenoviral hexon protein. Particularly, the heterologous sequenceencodes for an albumin-binding moiety.

The adenovirus particle consists on a capsid that encloses the viralDNA. The term “capsid”, as used herein, refers to the protein shell of avirus formed by subunits named capsomers that may be pentagonal orhexagonal. The adenoviral capsid has an icosahedral shape, which has 20equilateral triangular faces. Most of the capsid is formed by the hexonprotein and each vertex has a complex formed by penton base and fiberprotein.

The term “adenoviral hexon protein” or “hexon protein” (formerlyreferred to as “protein II”), as used herein, refers to the majorstructural capsid protein found in adenoviruses that self-associates toform trimers, each in the shape of a hexagon. 240 hexon trimers areassembled to provide an adenoviral capsid. The hexon protein isessential for virus capsid assembly, determination of the icosahedralsymmetry of the capsid and integrity of the capsid. The major structuralfeatures of the hexon protein are shared by adenoviruses acrossserotypes, but the hexon protein differs in size and immunologicalproperties between serotypes. In the present invention, the term “hexonprotein” encompasses the hexon protein of any adenovirus, including,without limitation, the protein defined by the sequence of the UniProtdatabase with accession number P04133 dated 19 Feb. 2014 whichcorresponds to the hexon protein of human adenovirus C serotype 5; theprotein defined by the sequence of the UniProt database with accessionnumber P03277 dated 19 Feb. 2014 which corresponds to the hexon proteinof human adenovirus C serotype 2; the protein defined by the sequence ofthe UniProt database with accession number P42671 dated 19 Feb. 2014which corresponds to the hexon protein of avian adenovirus gall (strainPhelps); and the protein defined by the sequence of the UniProt databasewith accession number P11819 dated 19 Feb. 2014 which corresponds to thehexon protein of human adenovirus F serotype 40. The expression includesall the natural variants of hexon protein that appear naturally in othersubgroups or serotypes.

In the present invention, the expression “outer surface of the hexonprotein”, refers to the regions of the hexon protein that are exposed onthe surface of the capsid. In order to know if the albumin-bindingmoiety of the present invention has been introduced in the inner part orin the outer surface of the adenoviral hexon protein, an assay fordetecting of binding to human serum albumin may be performed asdisclosed in the experimental section of this patent application (forexample, an ELISA assay) or an in vitro neutralization assay. If humanserum albumin is capable of binding to the adenovirus, then thealbumin-binding moiety has been introduced in the outer surface of theadenoviral hexon protein.

It has been reported that Loop 1 (L1) and Loop 2 (L2) of hexon proteinare exposed on the outside of the viral capsomere structure. L1 containssix hypervariable regions (HVRs), i.e. HVR1 to HVR6 and L2 contains theseventh hypervariable region (HVR7).

The term “hypervariable region” or “HVR”, as used herein, refers to aregion varying in length and sequence between adenoviral serotypesforming part of surfaced exposed loops. There are seven hypervariableregions of the adenoviral hexon for each subunit of the trimer (Biere Band Schweiger B. J Clin Virol 2010; 47(4):366-371). In the context ofthe present invention, the nomenclature used for the HVRs is asdisclosed in Crawford-Miksza and Schnurr (Crawford-Miksza and Schnurr.1996. Virology, 224(2):357-367). In a preferred embodiment of thepresent invention, the HVR is HVR1. Insertion of a specific residue inthe HVR region results in 240 times×3 or 720 total inserts peradenoviral vector. In a preferred embodiment the sequence encoding thealbumin-binding moiety is inserted so that the resulting fusion proteincontains the albumin-binding moiety after the D150 amino acid of thehexon protein according to the numbering of the hexon protein having theGenBank accession number BAG48782.1 dated 14 Jun. 2008 corresponding tohexon protein from human adenovirus serotype 5 (SEQ ID NO: 27). In amore preferred embodiment, the nucleotide sequence of the completemodified adenoviral hexon having ABD inserted in HVR1 (ABD-HVR1) is SEQID NO: 3. The inventors have demonstrated that insertion of thealbumin-binding domain in another HVR (specifically HVR5) producesviable virus but does not protect adenovirus from neutralizingantibodies. Examples of the present patent application show that thesequence encoding the albumin-binding moiety is inserted in HVR5 so thatthe resulting fusion protein contains the albumin-binding moiety afterthe A274 amino acid of the hexon protein according to the numbering ofthe hexon protein having the GenBank accession number BAG48782.1 dated14 Jun. 2008 corresponding to hexon protein from human adenovirusserotype 5 (SEQ ID NO: 27). The nucleotide sequence of the completemodified adenoviral hexon having ABD inserted in HVR5 (ABD-HVR5) is SEQID NO: 4. FIG. 12 shows that the albumin-binding domain is functionalwhen inserted in HVR1 but not in HVR5.

The albumin-binding moiety may be directly attached to the hexonprotein, i.e. the N- and C-terminus of the albumin-binding moiety arelinked directly to the hexon protein. However, it is also possible thatthe albumin-binding moiety is connected to the hexon protein by means ofa linker sequence. Thus, in another embodiment, the N- and/or theC-terminus of the albumin-binding moiety is connected to the hexonprotein by a linker sequence.

The term “linker sequence”, as used herein, refers to an amino acidsequence that acts as a hinge region between the hexon protein and thealbumin-binding moiety, providing space between both elements andassuring that the secondary structure of hexon protein is not affectedby the presence of the ABD moiety and vice versa. The linker sequencemay be of any length that allows both elements to move independentlyfrom one another while maintaining the three-dimensional form of theindividual elements. In a preferred embodiment, the linker sequence is aflexible linker peptide with a length of 31 amino acids or less. Morepreferably, the linker sequence comprises less than 10 amino acids, lessthan 5 amino acids, less than 4 amino acids or 2 amino acids. In anembodiment, the linker sequence comprises 2 or more amino acids selectedfrom the group consisting of glycine, serine, alanine and threonine. Inanother embodiment, said linker is a polyglycine linker. Exemplary,non-limitative, examples of linker sequences include SGGTSGSTSGTGST (SEQID NO: 5), AGSSTGSSTGPGSTT (SEQ ID NO: 6), GGSGGAP (SEQ ID NO: 7) andGGGVEGGG (SEQ ID NO: 8). These sequences have been used for bindingdesigned coiled coils to other protein domains (Muller, K. M. et al.Meth. Enzymology, 2000, 328:261-281). Preferably, the linker sequencecomprises the sequence GSGS (SEQ ID NO: 2). Other linkers known in theart could be used alternatively (Reddy Chichili, V P., Kumar, V., andSivaraman, J. (2013). Linkers in the structural biology ofprotein-protein interactions. Protein Science 22(2):153-67).

Therefore, the adenovirus of the present invention has analbumin-binding moiety on the outer surface of the hexon protein, thuscoating the capsid of the adenovirus with albumin.

The term “albumin”, as used herein, refers to a member of the albuminfamily proteins that are water-soluble globular proteins, moderatelysoluble in concentrated salt solutions and experiencing heatdenaturation. Albumins are commonly found in blood plasma. Serum albuminis produced by the liver, is dissolved in blood plasma and is the mostabundant blood protein in mammals. Particularly, the term “serumalbumin” refers to a globular protein that in humans is encoded by theALB gene (UniGene Hs. 418167). Human serum albumin protein is theprotein defined by the sequence of the Uniprot database with accessionnumber P02768 dated 19 Mar. 2014.

The term “albumin-binding moiety”, as used herein, refers to any aminoacid sequence capable of binding to albumin, i.e. having albumin bindingaffinity. Preferably, it is capable of binding serum albumin, morepreferably human serum albumin. The term “albumin-binding moiety”includes, without limitation, naturally-occurring albumin-bindingdomains (ABD) (such as ABD present in bacterial proteins), andalbumin-binding sequences from synthetic peptides. In a preferredembodiment, the albumin-binding moiety is selected from analbumin-binding domain from streptococcal protein G, an albumin-bindingdomain from Peptostreptococcus magnus protein PAB, an albumin-bindingpeptide having the core sequence DICLPRWGCLW (SEQ ID NO: 9) andfunctionally equivalent variants thereof. In a more preferredembodiment, the albumin-binding domain is from streptococcal protein G.

The term “albumin binding domain” refers to any region from a naturallyoccurring protein which is capable of binding albumin with sufficientspecificity so as to ensure protection from neutralizing antibodies.

The term “albumin-binding domain from streptococcal protein G”, or “ABDfrom streptococcal protein G”, as used herein, refers to a domain thatconsists of 46 amino acid residues forming a three-helix bundle (KraulisP. J. et al. FEBS Lett, 1996; 378:190-4), and binds with high affinityto both human and mouse albumin, but not to bovine albumin (Konig T. andSkerra A. J Immunol Methods, 1998; 218:73-83). There are multiplealbumin-binding domains in streptococcal protein G. In a preferreddomain the albumin-binding moiety is the albumin-binding domain 3 fromstreptococcal protein G. Preferably, the sequence of the albumin-bindingdomain 3 from streptococcal protein G is SEQ ID NO: 1.

The term “albumin-binding domain from Peptostreptococcus magnus proteinPAB”, as used herein, refers to the albumin-binding domain from proteinPAB of Finegoldia magna (formerly known as Peptostreptococcus magnus)known as the “GA module” that is capable of binding albumin (Lejon S etal. 2004. J Biol Chem 279:42924-42928). Protein PAB of Finegoldia magnais the protein defined by the sequence of the GenBank database withaccession number CAA54857.1 dated 9 Sep. 2004.

The term “albumin-binding peptide having the core sequence DICLPRWGCLW(SEQ ID NO: 9)”, as used herein, refers to peptides that bind albuminderived from phage clones RA and SA as disclosed in Dennis M S et al. (JBiol Chem. 2002. 277:35035-35043).

The invention also encompasses functionally equivalent variants of suchalbumin-binding moieties. The term “functionally equivalent variant”, asused herein, refers to any polypeptide derived from an albumin-bindingmoiety by insertion, deletion or substitution of one or more residuesand which maintains substantially the ability to interact with thealbumin as determined above. In a preferred embodiment, a polypeptide isconsidered a functionally equivalent variant of an albumin-bindingmoiety if it shows an ability in binding to albumin that is at least10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90% or 100% of the ability inbinding to albumin of the albumin-binding domain of SEQ ID NO: 1.Preferably, a polypeptide is considered a functionally equivalentvariant of an albumin-binding moiety if it is capable of neutralizingantibodies at least 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90% or 100%as efficiently as the albumin-binding domain of SEQ ID NO: 1.

Suitable functional variants are those showing a degree of identity withrespect to the albumin-binding domains or albumin-binding sequencesdisclosed in the present invention of at least 25% amino acid sequenceidentity, such as at least 30%, at least 40%, at least 50%, at least60%, at least 70%, at least 80%, at least 90%, at least 91%, at least92%, at least 93%, at least 94%, at least 95%, at least 96%, at least97%, at least 98% or at least 99%. The degree of identity between twopolypeptides is determined using computer algorithms and methods thatare widely known for the persons skilled in the art. The identitybetween two amino acid sequences is preferably determined by using theBLASTP algorithm [BLAST Manual, Altschul, S., et al., NCBI NLM NIHBethesda, Md. 20894, Altschul, S., et al., J. Mol. Biol. 215: 403-410(1990)], though other similar algorithms can also be used. BLAST andBLAST 2.0 are used, with the parameters described herein, to determinepercent sequence identity. Software for performing BLAST analyses ispublicly available through the National Center for BiotechnologyInformation.

The functionally equivalent variants of the albumin-binding moieties canbe derivatives of the albumin-binding domains and albumin-bindingsequences. The term “derivatives” includes, without limitation,albumin-binding domains from bacteria modified to increase theiraffinity to albumin, as those disclosed in Johansson M U. et al. (J BiolChem. 2002. 277:8114-8120), Jonsson A. et al. (Protein Eng Des Sel.2008. 21: 515-527) and Linhult M. et al. (Protein Sci. 2002.11:206-213). For example, a derivative may be the modified streptococcalG ABD ABD035 disclosed in Jonsson A. et al. (Protein Eng Des Sel. 2008.21: 515-527).

Recombinant adenoviruses may be obtained by standard molecular biologytechniques known in the state of the art (Chillon and Bosch. Adenovirus.Methods and Protocols. 3rd edition. Methods in Molecular Biology, vol.1089. Springer Protocols. Humana Press. (2014)).

The adenovirus that contains the albumin-binding moiety of the presentinvention is propagated and amplified following the standard methods inthe field of adenoviral vectors as disclosed in Chillon and Bosch.Adenovirus. Methods and Protocols. 3rd edition. Methods in MolecularBiology, vol. 1089. Springer Protocols. Humana Press. (2014); andAlemany R, Zhang W. Oncolytic adenoviral vectors. Totowa, N.J.: HumanaPress, 1999. Cell lines normally used in the field of gene therapy andvirotherapy are HEK-293 and A549 cell lines. The preferred method forpropagation is by infection of a cell line that allows the replicationof adenovirus. The lung adenocarcinoma A549 cell line is an example ofsuch a cell line. The propagation is carried out, for example, asfollows: A549 cells are seeded on plastic cell culture plates andinfected with 100 viral particles per cell. Two days later thecytopathic effect evidences the viral production when cells detachforming “grape-like” clusters. The cells are harvested in tubes. Aftercentrifugation at 1000 g during 5 minutes, the cell pellet is frozen andthawed three times to break the cells. The resulting cell extract iscentrifuged at 1000 g during 5 minutes and the supernatant containingthe virus is layered onto a cesium chloride gradient and centrifugedduring 1 hour at 35000 g. The band of virus obtained from the gradientis collected and layered again onto another gradient of cesium chlorideand centrifuged during 16 hours at 35000 g. The virus band is collectedand dialyzed against PBS-10% glycerol. The dialyzed virus is aliquotedand kept at −80° C. The quantification of the number of viral particlesand plaque-forming units is done following standard protocols. Phosphatebuffered saline (PBS) with 5% glycerol is a standard formulation usedfor the storage of adenovirus. Nevertheless other formulations thatimprove the stability of the virus have been described.

The methods of purification of the adenoviruses that contain thealbumin-binding moiety for its use in the prevention or treatment ofcancer are the same as those described for other adenoviruses andadenoviral vectors used in virotherapy and gene therapy of cancer.

Adenovirus can be used to target abnormal cells, for example, any cellswhich are harmful or otherwise unwanted in vivo. Broad examples includecells causing autoimmune disease, restenosis, and scar tissue formation.

The adenoviruses of the invention can be selectively distributed in vivoin a given tissue, avoiding or significantly reducing expression innon-target or non-tumour tissue.

The replicative adenovirus of the invention may have modifications inits genomic sequence that confer selective replication in a cell. Inorder to direct the expression of the adenovirus to the tissue whereinsuch expression is needed or to the tumoural tissue to be treated, theadenovirus of the invention may comprise a tissue-specific promoter or atumour-specific promoter. Thus, in an embodiment, the adenovirus furthercomprises a tissue-specific promoter or a tumour-specific promoter.

In a preferred embodiment, the tissue-specific promoter or thetumour-specific promoter are promoter sequences to control theexpression of one or more genes selected from the group consisting ofE1a, E1b, E2, and E4. Preferably, the promoter controls the expressionof E1a.

The term “promoter”, as used herein, is used according to itsart-recognized meaning. It is intended to mean the DNA region, usuallyupstream to the coding sequence of a gene, which binds RNA polymeraseand directs the enzyme to the correct transcriptional start site. Saidpromoter controls the viral genes that start the replication.

The term “tissue-specific” is intended to mean that the promoter towhich the gene essential for replication is operably linked functionsspecifically in that tissue so that replication proceeds in that tissue.This can occur by the presence in that tissue, and not in non-targettissues, of positive transcription factors that activate the promoter.It can also occur by the absence of transcription inhibiting factorsthat normally occur in non-target tissues and prevent transcription as aresult of the promoter. Thus, when transcription occurs, it proceedsinto the gene essential for replication such that in a target tissue,replication of the vector and its attendant functions occur.

Tissue specificity is particularly relevant with respect to targeting anabnormal counterpart of a particular tissue type while avoiding thenormal counterpart of the tissue, or avoiding surrounding tissue of adifferent type than the abnormal tissue, while treating the abnormaltissue. In a particular embodiment, the promoter is “tumour-specific”,which means that the promoter functions specifically in tumouraltissues. For example, the recombinant adenoviruses of the invention areuseful for treating metastases to the liver. One specific example iscolon cancer, which often metastasizes into the liver. It has been foundthat even when colon cancer metastasizes into the liver, the CEApromoter is active in the cells of the metastases but not in normalliver cells. Accordingly, normal human adult liver should not supportreplication of a virus that has viral genes essential for replicationlinked to the colon cancer CEA-specific promoter. Replication shouldoccur in the primary cancer cells. Another example is thealphafetoprotein promoter, which is active only in hepatocellularcarcinoma. A further example is the tyrosinase promoter, which is activeonly in melanoma and not in normal skin. In each case, replication isexpected in the abnormal but not the normal cells.

Examples of tissue-specific promoters are, without limitation,alphafetoprotein promoter, DE3 promoter, tyrosinase promoter,carcinoembryonic antigen (CEA) promoter, surfactant protein promoter,E2F promoter, telomerase hTERT promoter, prostate-specific antigenpromoter, COX-2 promoter, albumin gene promoter, the core promoter ofhepatitis virus, the promoter of the globulin-binding protein whichbinds to thyroxine and ErbB2 promoter.

In a preferred embodiment, the promoter is selected from the groupconsisting of a E2F promoter, a telomerase hTERT promoter, a tyrosinasepromoter, a prostate-specific antigen promoter, an alphafetoproteinpromoter, and a COX-2 promoter.

The adenoviruses of the invention are particularly useful for thetreatment of cancer. All tumours are potentially amenable to treatmentwith the adenovirus of the invention. Tumour types include, but are notlimited to, hematopoietic, pancreatic, neurologic, hepatic,gastrointestinal tract, endocrine, biliary tract, sinopulmonary, headand neck, soft tissue sarcoma and carcinoma, dermatologic, reproductivetract, and the like. Preferred tumours for treatment are those with ahigh mitotic index relative to normal tissue, preferably solid tumours.

In a preferred embodiment, the adenovirus of the invention is anoncolytic adenovirus.

The term “oncolytic adenovirus”, as used herein, refers to anyadenovirus that is able to replicate or that is replication-competent inthe tumour cell, even without selectivity. The therapeutic action ofoncolytic adenoviruses is based on the capability to replicate and tolyse the tumour cell to be eliminated. The death of the tumour cells canbe detected by any method of the state of the art, such as determiningthe number of viable cells, the cytopathic effect, the apoptosis oftumour cells, the synthesis of viral proteins in tumour cells (forexample, by metabolic labelling, Western blot of viral proteins or PCRwith reverse transcription of the viral genes needed for replication) orthe reduction in the size of the tumour.

Another strategy to achieve selective replication in tumours is thedeletion of viral functions that are necessary for replication in normalcells but that are not needed in tumour cells. This includes, forexample, the deletion of early E1A functions which block theretinoblastoma (pRB) pathway. The selective replication of such mutantshas been demonstrated in several prior art documents. Other viral genesthat interact directly with pRB such as E4 and E4orf6/7 are candidatesto be deleted in order to achieve selective replication in tumour cells.

Another modification described to achieve selective replication intumours is the deletion of adenoviral genes coding for thevirus-associated RNAs (VA-RNAs). These RNAs block the antiviral activityof interferon and their deletion results in adenoviruses that aresensitive to interferon inhibition. Due to the characteristic truncationin the interferon pathway in tumour cells such adenoviruses replicatenormally in tumours.

Therefore, in another embodiment the adenovirus of the invention furthercomprises mutations in one or more genes selected from the groupconsisting of E1a, E1b, E4, and VA-RNAs, to achieve selectivereplication in tumours. Preferably the mutations are in E1a. In apreferred embodiment the mutation in E1a is a deletion of some aminoacids of the E1A protein affecting the interaction of E1A with pRB,preferably is a deletion of the amino acids 121-129 of the polypeptidechain (Δ24 deletion).

The expression “selective replication”, as used herein, means that theadenovirus has replication efficiency in tumour cells higher than innormal cells (for example 1000-fold higher than in normal cells).

The term “replication”, as used herein, refers to the duplication ofadenoviral vectors that occur at the level of nucleic acid or at thelevel of infectious viral particle. In the case of DNA viruses,replication at the nucleic acid level is DNA replication. However,replication also includes the formation of infectious DNA viralparticles.

Replication of an adenovirus can be assayed by well-known techniques.Assays for replication of an adenoviral vector in a cell generallyinvolve detecting a polynucleotide, virions or infective virus. Avariety of well-known methods that can be used for this purpose involvedetermining the amount of a labelled substrate incorporated into apolynucleotide during a given period in a cell.

When replication involves a DNA polynucleotide, ³H-thymidine often isused as the labelled substrate. In this case, the amount of replicationis determined by separating DNA of the vector from the bulk of cellularDNA and measuring the amount of tritium incorporated specifically intovector DNA.

Replication of a polynucleotide vector also may be detected by lysing orpermeating cells to release the polynucleotide, then isolating thepolynucleotide and quantitating directly the DNA or RNA that isrecovered. Polynucleotide replication also may be detected byquantitative PCR using primers that are specific for the assayedpolynucleotide.

Virions may be assayed by electron microscope counting techniques wellknown to the art, by isolating the virions and determining protein andnucleic acid content, and by labelling viral genomic polynucleotides orvirion proteins and determining the amount of virion from the amount ofpolynucleotide or protein.

Another strategy to achieve selectivity of an adenovirus towards atumour cell is the modification of the virus capsid proteins implied inthe infection of the host cell to target the adenovirus to a receptorpresent in a tumour cell. The modification of the capsid proteins thatthe virus uses to infect the cells may also be used to increaseinfectivity of the adenovirus (i.e. increasing the entry of the virus inthe cell). Targeting adenovirus to the tumour can also be achieved withbifunctional ligands that bind to the virus in one end and to the tumourreceptor in the other.

Thus, in another embodiment the adenovirus of the invention furthercomprises capsid modifications to increase its infectivity or to targetit to a receptor present in a tumour cell. In a more preferredembodiment, the modification of the capsid is the insertion of an RGDmotif (Arginine-Glycine-Asparagine motif) into the H1 loop of theadenoviral fiber protein. This insertion allows the adenovirus to useintegrins to dock in the cell and not only to internalize as it is thecase with wild-type adenovirus. The use of integrins as cellularreceptors of the virus increases the infectivity and the oncolyticpotency. In another embodiment, the oncolytic adenovirus has the capsidmodified by means of a replacement of the KKTK (SEQ ID NO: 10) heparansulphate binding domain in the adenovirus fibre with the domain RGDK(SEQ ID NO: 11) (N. Bayo et al. Human Gene Therapy 2009, 20:1214-21).Another strategy to increase infectivity of target cells withadenoviruses is the replacement of a portion of the fiber with thehomologous portion from a different serotype. Commonly the fiber shaftand knob of human adenoviruses derived from serotype 5 have beenreplaced with the fiber shaft and knob of human serotype 3 or 35adenoviruses. The obtained recombinant adenoviruses with genomes derivedfrom different serotypes are known in the art as chimeric adenoviruses.In another embodiment the adenovirus of the invention further comprisesa chimeric capsid derived from different adenovirus serotypes. Inanother preferred embodiment, the modification of the capsid is thesubstitution of part of the fiber gene with the homologous part from adifferent adenovirus serotype to form a chimeric adenovirus.

In a preferred embodiment, the oncolytic adenovirus is atumour-selective replicating adenovirus characterized by containing amutant version of the E1A protein where amino acids 121-129 of thepolypeptide chain have been deleted (Δ24 deletion) affecting theinteraction of E1a with pRB, the insertion of four E2F binding sites andone Sp1 binding site in the endogenous promoter of E1a to control theexpression of E1a, and finally, the insertion of the RGD peptide in theadenoviral fibre to increase the infectivity of the virus. ICOVIR15-ABDis a preferred embodiment of the invention. Said modifications may bepresent in combination in the same adenovirus or in isolation.

In a preferred embodiment, the oncolytic adenovirus is atumour-selective replicating adenovirus characterized by containing adeletion of some amino acids of the E1A protein affecting theinteraction of E1A with pRB, preferably a deletion of the amino acids121-129 of the polypeptide chain (Δ24 deletion).

In another preferred embodiment, the oncolytic adenovirus is atumour-selective replicating adenovirus characterized by containing aninsertion of four E2F binding sites and one Sp1 binding site in theendogenous promoter of E1a to control the expression of E1a.

In another preferred embodiment, the oncolytic adenovirus is atumour-selective replicating adenovirus characterized by containing theinsertion of the RGD peptide in the adenoviral fibre to increase theinfectivity of the virus.

The genome of the adenovirus can also contain a heterologous gene thatencodes a therapeutic protein such that the heterologous gene isexpressed within an infected cell. A therapeutic protein, as usedherein, refers to a protein that would be expected to provide sometherapeutic benefit when expressed in a given cell. Said heterologousgene products may be contained in replicating or non-replicatingadenovirus. The therapeutic gene inserted may be any gene used in genetherapy or in vaccination. Preferably, the heterologous gene is used incancer gene therapy. The insertion of a therapeutic gene in the genomeof the oncolytic adenovirus generates an “armed oncolytic adenovirus”that increase the cytotoxicity of oncolytic adenovirus towards tumourcells. For example, said heterologous gene can produce the death of thetumour cell, activate the immune system against the tumour, inhibit theangiogenesis, eliminate the extracellular matrix, induction of theapoptosis, among others. In these cases, the way and the time ofexpression of the therapeutic gene will be critical in the final resultof the therapeutic approach.

Therefore, in an embodiment, the adenovirus comprises one or morenon-adenoviral genes inserted in the genome of said adenovirus. In apreferred embodiment, the genes are genes used in gene therapy or invaccination. In a more preferred embodiment the genes are genes used incancer gene therapy. Preferably, the genes used in cancer gene therapyare at least a gene selected from the group consisting ofprodrug-activating genes, tumour-suppressor genes, genes encodinganti-tumour interfering RNAs and immunostimulatory genes.

The term “non-adenoviral gene”, as used herein, refers to a heterologousgene not present in the genome of a wild-type adenovirus.

The term “gene used in gene therapy”, as used herein, refers to a genethat can be used as a drug to prevent or treat a genetic or acquireddisease or condition by delivering said therapeutic DNA into patient'scells. As the person skilled in the art understands, the term genetherapy involves using DNA that encodes a functional, therapeutic geneto replace a mutated gene or using DNA that encodes a therapeuticprotein. For example, the DNA can encode an enzyme, hormone, receptor orpolypeptide of therapeutic value. Any gene that can be used to treat adisease that is suitable treated by gene therapy may be inserted in theadenoviral genome of the adenovirus of the invention. Genes used in genetherapy can be, without limitation, genes coding for enzymes, bloodderivatives, hormones, interleukins, interferons, TNF, growth factors,neurotransmitters or their precursors or synthetic enzymes, trophicfactors, namely BDNF, CNTF, NGF, IGF, GMF, aFGF, bFGF, NT3, NT5 and thelike; apolipoproteins, namely ApoAI, ApoAIV, ApoE, and the like;dystrophin or a minidystrophin;

tumour-suppressor genes, namely p53, Rb, RaplA, DCC, k-rev; genes codingfor factors involved in coagulation, namely factors VII, VIII, IX;prodrug-activating genes, namely thymidine kinase, cytosine deaminase;all or part of a natural or artificial immunoglobulin (Fab, ScFv, andthe like). The therapeutic gene can also be an antisense gene orsequence whose expression in the target cell enables gene expression ortranscription of cellular mRNAs to be controlled.

The term “gene used in vaccination”, as used herein, refers to a genecoding for an antigenic peptide, capable of generating an immuneresponse in man or animals for the purpose of preventive or therapeuticvaccine production. Such antigenic peptides may be, without limitation,those specific to the Epstein-Barr virus, the HIV virus, the hepatitis Bvirus, the pseudorabies virus and tumour-specific peptides.

The term “prodrug-activating genes”, as used herein, refers to genesencoding a product that acts on a non-toxic prodrug, converting thenon-toxic prodrug into a form that is toxic for the target tissue.Preferably, the toxin has anti-tumour activity or eliminates cellproliferation.

Examples of prodrug-activating genes include, without limitation,thymidine kinase gene. Herpes simplex virus thymidine kinasephosphorylates ganciclovir to produce the nucleotide toxin ganciclovirphosphate. This compound functions as a chain terminator and DNApolymerase inhibitor, prevents DNA synthesis and thus is cytotoxic. Inan embodiment the prodrug-activating gene is thymidine kinase gene,preferably a viral thymidine kinase selected from the group consistingof Herpes simplex virus thymidine kinase, cytomegalovirus thymidinekinase and varicella-zoster virus thymidine kinase. When viral thymidinekinases are employed, the interaction or chemotherapeutic agentpreferably is a nucleoside analogue, for example, one selected from thegroup consisting of ganciclovir, acyclovir, and1-2-deoxy-2-fluoro-D-arabinofuranosil-5-iodouracil (FIAU). Suchinteraction agents are utilized efficiently by the viral thymidinekinases as substrates, and such interaction agents thus are incorporatedlethally into the DNA of the tumour cells expressing the viral thymidinekinases, thereby resulting in the death of the target cells. In anotherembodiment the prodrug-activating gene is cytosine deaminase. Cytosinedeaminase converts 5′-fluorocytosine to the anticancer drug5′-fluorouracil, which is highly cytotoxic. Thus, the target cell whichexpresses the cytosine deaminase gene converts the 5-fluorocytosine to5-fluorouracil and are killed. For a discussion of such “suicide” genes,see Blaese, R. M. et al., Eur. J. Cancer 30A:1190-1193 (1994).

The term “tumour-suppressor genes”, as used herein, refers toanti-oncogenes or genes that protect a cell from one step on the path tocancer. When one of these genes mutates to cause a loss or reduction inits function, the cell can progress to cancer, usually in combinationwith other genetic changes.

Examples of tumour-suppressor genes are, without limitation, p53tumour-suppressor protein encoded by the TP53 gene, PTEN, pVHL, APC,CD95, ST5, YPEL3, ST7, and ST14.

The term “genes encoding antitumour interfering RNAs”, as used herein,refers to genes that encode therapeutically useful RNA molecules for thetreatment of tumours, i.e. siRNA (Dorsett and Tuschl (2004) Nature RevDrug Disc 3:318-329). In some cases, genes can be incorporated into arecombinant adenovirus of the invention to further enhance the abilityof the adenovirus to eradicate the cell of the monocyte/macrophagelineage, although not having any direct impact on the cell itself. Theseinclude genes encoding siRNAs capable of inhibit the activity of factorsthat compromise MHC class I presentation, block complement, inhibit IFNsand IFN-induced mechanisms, chemokines and cytokines, NK cell basedkilling, down regulate the immune response (e.g. IL-10, TGF-Beta) andmetalloproteases which can breakdown the extracellular matrix andenhance spread of the virus within the tumour.

The term “immunostimulatory genes”, as used herein, refers to genes thatactivate the immune system against the tumour. Further examples ofheterologous genes, or fragments thereof, include those that encodeimmunomodulatory proteins, such as cytokines or chemokines. Examplesinclude interleukin 2, U.S. Pat. No. 4,738,927 or 5,641,665; interleukin7, U.S. Pat. No. 4,965,195 or 5,328,988; and interleukin 12, U.S. Pat.No. 5,457,038; tumour necrosis factor alpha, U.S. Pat. No. 4,677,063 or5,773,582; interferon gamma, U.S. Pat. No. 4,727,138 or 4,762,791; or GMCSF, U.S. Pat. No. 5,393,870 or 5,391,485, Mackensen et al. (1997)Cytokine Growth Factor Rev. 8:119-128).

These modifications in the genome of the adenovirus are not excludingeach other.

Adenoviral Genomes of the Invention

The present invention is also directed to the genome of the adenovirus.In an aspect, the invention relates to an adenoviral genomecharacterized in that it comprises a sequence encoding analbumin-binding moiety inserted in the coding region of thehypervariable region 1 (HVR1) of the hexon protein which results in theexpression of fusion protein comprising a hexon protein and analbumin-binding moiety and wherein the albumin-binding moiety is locatedon the outer surface of the hexon protein when the hexon protein isassembled in the adenovirus capsid.

The expression “adenoviral genome”, as used herein, refers to adouble-stranded DNA sequence that, in the presence of appropriateproteins, can be packaged, resulting in a complete adenovirus particle.For this packaging to occur, the sequence must comply with someconditions, which can be summarized as follows:

-   -   exhibit separate adenovirus ITR, one at each of its end points;    -   comprise a packaging signal Psi between both ITRs, located in        such a way that the distance between the 5′ end of the packaging        signal Psi and the 3′ end of the ITR closest to it does not        exceed the distance that would prevent packaging of the natural        adenovirus, a distance that is 200 base pairs in the case of the        human serotype 5 adenovirus and which is assumed, by analogy, to        be approximately equal in the case of other serotypes, since it        has been seen that the introduction of sequences between the ITR        and the packaging signal in the sequence that naturally        separates them decreases the packaging capacity of the        adenoviral genome, causing a reduction in the total number of        adenovirus particles obtained, even though there is no        significant change in the time necessary for their packaging;    -   the distance between the ends of both ITR should not be greater        than 105 percent of the size of the adenovirus genome present in        nature to which the proteins which will form the capsid belong.

The adenoviral genome is preferably deficient in at least one genefunction required for viral replication, thereby resulting in a“replication-deficient” adenoviral vector. By “replication-deficient” ismeant that the adenoviral vector comprises an adenoviral genome thatlacks at least one replication-essential gene function (i.e., such thatthe adenoviral vector does not replicate in typical host cells,especially those in a human patient that could be infected by theadenoviral vector in the course of treatment in accordance with theinvention).

More preferably, the replication-deficient adenoviral vector comprisesan adenoviral genome deficient in at least one replication-essentialgene function of one or more regions of the adenoviral genome. In thisrespect, the adenoviral vector is deficient in at least one essentialgene function of the E4 region or E1 region of the adenoviral genomerequired for viral replication. In addition to a deficiency in the E1region, the recombinant adenovirus can also have a mutation in the majorlate promoter (MLP). More preferably, the adenoviral vector is deficientin at least one essential gene function of the E1 region and at leastpart of the E3 region (e.g., an Xba I deletion of the E3 region). Withrespect to the E1 region, the adenoviral vector can be deficient in(e.g., deleted of) at least part of the E1a region and at least part ofthe E1b region. For example, the adenoviral vector can comprise adeletion of the entire E1 region and part of the E3 region of theadenoviral genome (i.e., nucleotides 355 to 3,511 and 28,593 to 30,470).A singly-deficient adenoviral vector can be deleted of approximatelynucleotides 356 to 3,329 and 28,594 to 30,469 (based on the adenovirusserotype 5 genome). Alternatively, the adenoviral vector genome can bedeleted of approximately nucleotides 356 to 3,510 and 28,593 to 30,470(based on the adenovirus serotype 5 genome), thereby resulting in anadenoviral vector having deletions in the E1, E3, and E4 regions of theadenoviral genome.

A deficiency in a gene, gene function, or gene or genomic region, asused herein, is defined as a deletion of sufficient genetic material ofthe viral genome to impair or obliterate the function of the gene whosenucleic acid sequence was deleted in whole or in part. Deletion of anentire gene region often is not required for disruption of areplication-essential gene function. However, for the purpose ofproviding sufficient space in the adenoviral genome for one or moretransgenes, removal of a majority of a gene region may be desirable.While deletion of genetic material is preferred, mutation of geneticmaterial by addition or substitution also is appropriate for disruptinggene function. Replication-essential gene functions are those genefunctions that are required for replication (e.g., propagation) and areencoded by, for example, the adenoviral early regions (e.g., the E1, E2,and E4 regions), late regions (e.g., the L1-L5 regions), genes involvedin viral packaging (e.g., the IVa2 gene), and virus-associated RNAs(e.g., NA-RNA-1 and/or NA-RNA-2).

The adenoviral vector also can have essentially the entire adenoviralgenome removed except the ITR and the packaging sequence. Such vectorsare known in the art as gutless or helper-dependent adenovirus vectors.In this case the hexon sequence modified to contain an albumin bindingmoiety is provided by the helper adenovirus. The 5′ or 3′ regions of theadenoviral genome comprising ITRs and packaging sequence need notoriginate from the same adenoviral serotype as the remainder of theviral genome. For example, the 5′ region of an adenoviral serotype 5genome (i.e., the region of the genome 5′ to the adenoviral E1 region)can be replaced with the corresponding region of an adenoviral serotype2 genome (e.g., the Ad5 genome region 5′ to the E1 region of theadenoviral genome is replaced with nucleotides 1-456 of the Ad2 genome).However, the deficiencies of the adenoviral genome of the adenoviralvector of the inventive method preferably are limited toreplication-essential gene functions encoded by the early regions of theadenoviral genome.

According to the invention, inverted terminal repeat or ITR isunderstood as sequences of approximately 100 base pairs which are onboth sides of the linear genome of the adenovirus and which areessential for the replication of the adenoviral genome (Stow, N. D.,1982, Nucl. Acid. Res, 10:5105-5109).

According to the invention, adenoviral packaging signal w is understoodas a sequence of approximately 160 base pairs long which, in the case ofthe adenovirus of serotypes 2 and 5, extends between positions 190 and350 of the genome. The elimination of the sequence of the genome of anadenovirus prevents the DNA molecules which are generated during themultiplication of the virus from being efficiently incorporated to therecently formed capsids (Hearing, P. et al., 1987, J. Virol.,61:2555-2558), but they do not prevent the replication of said genome inthe packaging cell, unlike the elimination of ITRs.

All the embodiments disclosed in the context of the adenoviruses of theinvention are applicable to the adenoviral genomes of the invention.

Particularly, in an embodiment the adenoviral genome is from a humanadenovirus, preferably selected from the group consisting of humanadenovirus serotypes 1 to 57, more preferably serotype 5.

In another embodiment the albumin-binding moiety is selected from analbumin-binding domain from streptococcal protein G, an albumin-bindingdomain from Peptostreptococcus magnus protein PAB, an albumin-bindingpeptide having the core sequence DICLPRWGCLW (SEQ ID NO: 9) andfunctionally equivalent variants thereof. In a more preferredembodiment, the albumin-binding moiety is the albumin-binding domain 3from streptococcal protein G, preferably having the sequence SEQ ID NO:1.

In another embodiment the sequence encoding the albumin-binding moietyis inserted so that the resulting fusion protein contains thealbumin-binding moiety after the D150 amino acid of the hexon proteinaccording to the numbering of the hexon protein having the GenBankaccession number BAG48782.1 (SEQ ID NO: 27). In a preferred embodiment,the nucleotide sequence of the complete modified adenoviral hexon havingABD inserted in HVR1 (ABD-HVR1) is SEQ ID NO: 3.

In another embodiment the N- and/or the C-terminus of thealbumin-binding moiety is connected to the hexon protein by a linkersequence, preferably a linker sequence comprising the sequence GSGS (SEQID NO: 2).

In another embodiment the adenoviral genome further comprises atissue-specific promoter or a tumour-specific promoter. In a preferredembodiment the tissue-specific promoter or the tumour-specific promoterare promoter sequences to control the expression of one or more genesselected from the group consisting of E1a, E1b, E2, and E4; morepreferably a promoter selected from the group consisting of a E2Fpromoter, a telomerase hTERT promoter, a tyrosinase promoter, aprostate-specific antigen promoter, an alpha-fetoprotein promoter, and aCOX-2 promoter.

In another embodiment the adenovirus is an oncolytic adenovirus,preferably an adenovirus wherein its adenoviral genome further comprisesmutations in one or more genes selected from the group consisting ofE1a, E1b, E4, and VA-RNAs, to achieve selective replication in tumours.

In another embodiment the adenoviral genome further comprises capsidmodifications to increase adenovirus infectivity or to target it to areceptor present in a tumour cell. Preferably, the modification of thecapsid is the insertion of an RGD motif into the H1 loop of theadenoviral fiber protein. In another embodiment the adenoviral genome isa chimeric adenovirus genome derived from one given serotype thatcontains a fragment or portion of its genome replaced by the homologousportion of the genome from another serotype. Preferably, the saidchimeric adenovirus is a human adenovirus from the serotype 5 whichcontains a portion of the fiber gene replaced with the homologousportion from another serotype, preferably human adenovirus 3 or humanadenovirus 35. In a preferred embodiment, the modification of the capsidis the substitution of part of the fiber gene with the homologous partfrom a different adenovirus serotype to form a chimeric adenovirus.

In another embodiment, the adenoviral genome comprises further genesinserted in said genome. In an embodiment, said genes are used in genetherapy or in vaccination. Preferably, said genes are genes used incancer gene therapy, more preferably are at least a gene selected fromthe group consisting of prodrug-activating genes, tumour-suppressorgenes, genes encoding anti-tumour interfering RNAs, andimmunostimulatory genes.

Compositions of the Invention

The recombinant adenoviruses of the invention can be used to prepare apharmaceutical composition. Thus, another aspect of the presentinvention is a pharmaceutical composition comprising a therapeuticallyeffective amount of a recombinant adenovirus according to the inventiontogether with a pharmaceutically acceptable carrier.

As it is used in the present invention, the expression “pharmaceuticalcomposition” relates to a formulation that has been adapted foradministering a predetermined dose of one or several therapeutic usefulagents to a cell, a group of cells, an organ, a tissue or an organism.

The recombinant adenoviruses are administered in effective amounts. A“therapeutically effective amount” is understood as an amount capable ofproviding a therapeutic effect, and which can be determined by theperson skilled in the art by commonly used means. The effective amountwill vary with the particular condition being treated, the age andphysical condition of the subject being treated, the severity of thecondition, the duration of the treatment, the nature of the concurrentor combination therapy (if any), the specific route of administrationand like factors within the knowledge and expertise of the healthpractitioner. It is preferred generally that a maximum dose be used,that is, the highest safe dose according to sound medical judgment. Forexample, if the subject has a tumour, an effective amount may be thatamount that reduces the tumour volume or load (as for example determinedby imaging the tumour). Effective amounts may also be assessed by thepresence and/or frequency of cancer cells in the blood or other bodyfluid or tissue (e.g., a biopsy). If the tumour is impacting the normalfunctioning of a tissue or organ, then the effective amount may beassessed by measuring the normal functioning of the tissue or organ.Those skilled in the art will appreciate that dosages may also bedetermined with guidance from Goodman and Goldman's The PharmacologicalBasis of Therapeutics, Ninth Edition (1996), Appendix II, pp. 1707-1711and from Goodman and Goldman's The Pharmacological Basis ofTherapeutics, Tenth Edition (2001), Appendix II, pp. 475-493.

As used herein, the term “pharmaceutically acceptable carrier” means anon-toxic, inert solid, semi-solid or liquid filler, diluent,encapsulating material or formulation auxiliary of any type that isacceptable to the patient from a pharmacological/toxicological point ofview and to the manufacturing pharmaceutical chemist from aphysical/chemical point of view regarding composition, formulation,stability, patient acceptance and bioavailability. Remington'sPharmaceutical Sciences. Ed. by Gennaro, Mack Publishing, Easton, Pa.,1995 discloses various carriers used in formulating pharmaceuticalcompositions and known techniques for the preparation thereof. Someexamples of materials which can serve as pharmaceutically acceptablecarriers include, but are not limited to, sugars such as lactose,glucose, and sucrose; starches such as corn starch and potato starch;cellulose and its derivatives such as sodium carboxymethyl cellulose,ethyl cellulose, and cellulose acetate; powdered tragacanth; malt;gelatin; talc; excipients such as cocoa butter and suppository waxes;oils such as peanut oil, cottonseed oil; safflower oil; sesame oil;olive oil; corn oil and soybean oil; glycols such as propylene glycol;esters such as ethyl oleate and ethyl laurate; agar; detergents such asTWEEN™ 80; buffering agents such as magnesium hydroxide and aluminiumhydroxide; alginic acid; pyrogen-free water; isotonic saline; Ringer'ssolution; ethyl alcohol; and phosphate buffer solutions, as well asother non-toxic compatible lubricants such as sodium lauryl sulphate andmagnesium stearate, as well as colouring agents, releasing agents,coating agents, sweetening, flavouring and perfuming agents,preservatives and antioxidants can also be present in the composition,according to the judgment of the formulator. If filtration or otherterminal sterilization methods are not feasible, the formulations can bemanufactured under aseptic conditions.

The pharmaceutical compositions of this invention can be administered toa patient by any means known in the art including oral and parenteralroutes. According to such embodiments, the compositions of the inventionmay be administered by injection (e.g., intravenous, subcutaneous orintramuscular, intraperitoneal injection). In a particular embodiment,the recombinant adenoviruses of the present invention are administeredto a subject in need thereof systemically, e.g. by IV infusion orinjection. Injectable preparations, for example, sterile injectableaqueous or oleaginous suspensions may be formulated according to theknown art using suitable dispersing or wetting agents and suspendingagents. The sterile injectable preparation may also be a sterileinjectable solution, suspension, or emulsion in a nontoxic parenterallyacceptable diluent or solvent, for example, as a solution in1,3-butanediol. Among the acceptable vehicles and solvents that may beemployed are water, Ringer's solution, U.S.P., and isotonic sodiumchloride solution. In addition, sterile, fixed oils are conventionallyemployed as a solvent or suspending medium. For this purpose any blandfixed oil can be employed including synthetic mono- or diglycerides. Inaddition, fatty acids such as oleic acid are used in the preparation ofinjectables. In one embodiment, the recombinant adenovirus is suspendedin a carrier fluid comprising 1% (w/v) sodium carboxymethyl celluloseand 0.1% (v/v) TWEEN™ 80. The injectable formulations can be sterilized,for example, by filtration through a bacteria-retaining filter, or byincorporating sterilizing agents in the form of sterile solidcompositions which can be dissolved or dispersed in sterile water orother sterile injectable medium prior to use.

The compositions can comprise the recombinant adenovirus as the onlyagent or in combination with another therapeutic agent.

In a preferred embodiment the composition comprises an oncolyticadenovirus or an adenovirus comprising one or more genes used in cancergene therapy inserted in the genome of the adenovirus. In thisparticular case, the compositions can comprise this adenovirus as theonly agent against the tumour, or in combination with anothertherapeutic agent such as a chemotherapy drug or a vector with aninserted therapeutic gene.

Therapeutic Uses of the Adenovirus of the Invention

There is broad experience in the use of replication-defective andreplication-competent adenoviruses in the field of gene therapy and inthe field of vaccination.

In a further aspect, the invention relates to a recombinant adenovirusof the invention or a pharmaceutical composition according to theinvention for use in medicine. The adenoviruses of the invention may bedesigned to treat any kind of disease that requires the administrationof such adenovirus into the bloodstream.

The inventors have also shown that the adenoviruses of the invention areparticularly useful for the treatment of cancer.

In another aspect, the invention relates to a recombinant adenovirus ofthe invention or a pharmaceutical composition according to the inventionfor use in the prevention and/or treatment of cancer in a mammal,wherein the adenovirus is an oncolytic adenovirus or an adenoviruscomprising one or more genes used in cancer gene therapy inserted in thegenome of the adenovirus.

Alternatively, the invention relates to the use of a recombinantadenovirus of the invention or a pharmaceutical composition according tothe invention for the manufacture of a medicament for the preventionand/or treatment of cancer in a mammal, wherein the adenovirus is anoncolytic adenovirus or an adenovirus comprising one or more genes usedin cancer gene therapy inserted in the genome of the adenovirus.

Alternatively, the invention relates to a method for the preventionand/or treatment of cancer in a mammal comprising administering to saidmammal a recombinant adenovirus of the invention or a pharmaceuticalcomposition according to the invention, wherein the adenovirus is anoncolytic adenovirus or an adenovirus comprising one or more genes usedin cancer gene therapy inserted in the genome of the adenovirus.

The term “prevention”, as used herein, refers to a prophylactic orpreventive method, wherein the adenovirus is administered in an initialor early stage of the disease (i.e. premalignant stage of a tumour), orto also prevent its onset.

Adenovirus vectors have been commonly used to prepare vaccines thatelicit immunity against proteins of pathogens. For example, recombinantadenovirus vaccines have been publicly described against HIV, rabiesvirus, dengue virus, ebola virus, sars coronavirus, humanpapillomavirus, hepatitis C virus, hepatitis B virus, rotavirus, measlesvirus, respiratory syncytial virus, cytomegalovirus, herpes simplex 2virus, Epstein barr virus, influenza virus, Trypanosoma cruzi andPlasmodium falciparum, against others.

In another aspect, the invention relates to a recombinant adenovirus ofthe invention or a pharmaceutical composition according to the inventionfor use in the prevention of an infectious disease in a mammal.

Alternatively, the invention relates to the use of a recombinantadenovirus of the invention or a pharmaceutical composition according tothe invention for the manufacture of a medicament, preferably a vaccine,for the prevention of an infectious disease in a mammal.

Alternatively, the invention relates to a method for the prevention ofan infectious disease in a mammal comprising administering to saidmammal a recombinant adenovirus of the invention or a pharmaceuticalcomposition according to the invention.

The expressions “infectious disease” or “infection”, as used herein,refer to a disease caused by the invasion of a host organism by aninfectious or pathogenic agent such as viruses, viroids and prions;microorganisms such as bacteria; parasites such as nematodes (includingroundworms and pinworms), arthropods such as ticks, mites, fleas andlice; fungi and protozoa.

The recombinant adenoviruses of the invention are suitable for themanufacture of vaccines for the prevention of any kind of infectiousdisease.

In a preferred embodiment the infectious disease is caused by apathogenic agent selected from the group consisting of HIV, rabiesvirus, dengue virus, ebola virus, sars coronavirus, humanpapillomavirus, hepatitis C virus, hepatitis B virus, rotavirus, measlesvirus, respiratory syncytial virus, cytomegalovirus, herpes simplex 2virus, Epstein barr virus, influenza virus, Trypanosoma cruzi andPlasmodium falciparum.

The term “treat” or “treatment” refers to a therapeutic treatment,wherein the goal is to control the progression of the disease before orafter the clinical signs have appeared. Control of the progression ofthe disease is understood as the beneficial or desired clinical resultswhich include but are not limited to reduction of the symptoms,reduction of the duration of the disease, stabilization of pathologicalconditions (specifically avoiding additional impairment), delaying theprogression of the disease, improving the pathological condition andremission (both partial and complete). The control of the progression ofthe disease also involves a prolongation of survival in comparison tothe expected survival if the treatment was not applied.

For example, in the case of treating cancer, a response could bemonitored by observing one or more of the following effects: (1)inhibition, to some extent, of tumour growth, including, (i) slowingdown (ii) inhibiting angiogenesis and (ii) complete growth arrest; (2)reduction in the number of tumour cells; (3) maintaining tumour size;(4) reduction in tumour size; (5) inhibition, including (i) reduction,(ii) slowing down or (iii) complete prevention, of tumour cellinfiltration into peripheral organs; (6) inhibition, including (i)reduction, (ii) slowing down or (iii) complete prevention, ofmetastasis; (7) enhancement of anti-tumour immune response, which mayresult in (i) maintaining tumour size, (ii) reducing tumour size, (iii)slowing the growth of a tumour, (iv) reducing, slowing or preventinginvasion and/or (8) relief, to some extent, of the severity or number ofone or more symptoms associated with the disorder.

The term “cancer” is referred to a disease characterized by uncontrolledcell division (or by an increase of survival or apoptosis resistance),by the ability of said cells to invade other neighbouring tissues(invasion) or by the spread to other areas of the body where the cellsare not normally located (metastasis) through the lymphatic and bloodvessels. As used herein, the term cancer includes, but is not limitedto, the following types of cancer: breast cancer; biliary tract cancer;bladder cancer; brain cancer including glioblastomas andmedulloblastomas; cervical cancer; choriocarcinoma; colon cancer;endometrial cancer; esophageal cancer; gastric cancer; hematologicalneoplasms including acute lymphocytic and myelogenous leukemia; T-cellacute lymphoblastic leukemia/lymphoma; hairy cell leukemia; chronicmyelogenous leukemia, multiple myeloma; AIDS-associated leukemias andadult T-cell leukemia/lymphoma; intraepithelial neoplasms includingBowen's disease and Paget's disease; liver cancer; lung cancer;lymphomas including Hodglun's disease and lymphocytic lymphomas;neuroblastomas; oral cancer including squamous cell carcinoma; ovariancancer including those arising from epithelial cells, stromal cells,germ cells and mesenchymal cells; pancreatic cancer; prostate cancer;rectal cancer; sarcomas including leiomyosarcoma, rhabdomyosarcoma,liposarcoma, fibrosarcoma, and osteosarcoma; skin cancer includingmelanoma, Merkel cell carcinoma, Kaposi's sarcoma, basal cell carcinoma,and squamous cell cancer; testicular cancer including germinal tumourssuch as seminoma, non-seminoma (teratomas, choriocarcinomas), stromaltumours, and germ cell tumours; thyroid cancer including thyroidadenocarcinoma and medullar carcinoma; and renal cancer includingadenocarcinoma and Wilms tumour. In an embodiment the cancer is breastcancer. In another embodiment the cancer is melanoma. Other cancerswill-be known to one of ordinary skill in the art.

The adenovirus of the present invention can be administered to a mammal.The term “mammal”, as used herein, refers to any mammalian species,including but not being limited to domestic and farm animals (cows,horses, pigs, sheep, goats, dogs, cats or rodents), primates, andhumans. Preferably, the mammal is a human being. In the context of thepresent invention, the mammal is suffering from cancer or in risk ofsuffering from cancer.

To treat tumours in animal models or patients adenoviruses can bedelivered by local or regional administration through intratumoural orintracavital injection or systemically by injection into thebloodstream. The virus can also be administered in the vasculature ofthe tumour. Since the recombinant adenoviruses of the invention areprotected against neutralizing antibodies present in the bloodstream,they are particularly suitable for systemic administration. Therefore,in a preferred embodiment the adenovirus of the invention issystemically administered. The expression “systemically administered”,as used herein, refers to a route of administration into the circulatorysystem so that the entire body is affected. Preferably theadministration is parenteral (generally intraarterial or endovenousinjection, infusion or implantation).

The adenovirus of the invention is ideally administered before havingbeen bound to serum albumin and it binds to albumin in the blood of thesubject treated. However, to increase the blood persistence ofadenoviruses in order to increase the possibilities of reaching thedisseminated tumour nodes, the capsid can be coated with albumin beforethe adenovirus is administered.

The treatment of tumours with the adenoviruses of the invention can beused in combination with other therapeutic modalities like chemotherapyor radiotherapy, as previously described in the field of oncolyticadenovirus.

Protocols for using the adenoviruses described in the present inventionfor the treatment of cancer are the same procedures used in the fieldsof virotherapy and gene therapy with adenovirus.

The present invention is also directed to:

-   [1]. An adenoviral genome characterized in that it comprises a    sequence encoding an albumin-binding moiety inserted in the coding    region of a hypervariable region (HVR) of the hexon protein which    results in the expression of fusion protein comprising a hexon    protein and an albumin-binding moiety and wherein the    albumin-binding moiety is located on the outer surface of the hexon    protein when the hexon protein is assembled in the adenovirus    capsid.-   [2]. The adenoviral genome according to [1], wherein the genome is    from a human adenovirus.-   [3]. The adenoviral genome according to [2], wherein the human    adenovirus is selected from the group consisting of human adenovirus    serotypes 1 to 57.-   [4]. The adenoviral genome according to [3], wherein the human    adenovirus is serotype 5.-   [5]. The adenoviral genome according to [1], [2], [3] or [4],    wherein the albumin-binding moiety is selected from an    albumin-binding domain from streptococcal protein G, an    albumin-binding domain from Peptostreptococcus magnus protein PAB,    an albumin-binding peptide having the core sequence DICLPRWGCLW (SEQ    ID NO: 9) and functionally equivalent variants thereof.-   [6]. The adenoviral genome according to [5], wherein the    albumin-binding moiety is the albumin-binding domain 3 from    streptococcal protein G.-   [7]. The adenoviral genome according to [6], wherein the sequence of    the albumin-binding domain 3 from streptococcal protein G is SEQ ID    NO: 1.-   [8]. The adenoviral genome according to [1], [2], [3], [4], [5], [6]    or [7], wherein the HVR of the hexon protein is selected from the    group consisting of HVR1, HVR2, HVR3, HVR4, HVR5, HVR6 and HVR7.-   [9]. The adenoviral genome according to [8], wherein the HVR of the    hexon protein is HVR1.-   [10]. The adenoviral genome according to [9], wherein the sequence    encoding the albumin-binding moiety is inserted so that the    resulting fusion protein contains the albumin-binding moiety after    the D150 amino acid of the hexon protein according to the numbering    of the hexon protein having the GenBank accession number BAG48782.1    (SEQ ID NO: 27).-   [11]. The adenoviral genome according to [8], wherein the HVR of the    hexon protein is HVR5.-   [12]. The adenoviral genome according to [11], wherein the sequence    encoding the albumin-binding moiety is inserted so that the    resulting fusion protein contains the albumin-binding moiety after    the A274 amino acid of the hexon protein according to the numbering    of the hexon protein having the GenBank accession number BAG48782.1    (SEQ ID NO: 27).-   [13]. The adenoviral genome according to any of [1] to [12], wherein    the N- and/or the C-terminus of the albumin-binding moiety is    connected to the hexon protein by a linker sequence.-   [14]. The adenoviral genome according to [13], wherein said linker    sequence comprises the sequence GSGS (SEQ ID NO: 2).-   [15]. The adenoviral genome according to any of [1] to [14], wherein    said adenoviral genome further comprises a tissue-specific promoter    or a tumour-specific promoter.-   [16]. The adenoviral genome according to [15], wherein the    tissue-specific promoter or the tumour-specific promoter are    promoter sequences to control the expression of one or more genes    selected from the group consisting of E1a, E1b, E2, and E4.-   [17]. The adenoviral genome according to [16], wherein the promoter    is selected from the group consisting of a E2F promoter, a    telomerase hTERT promoter, a tyrosinase promoter, a    prostate-specific antigen promoter, an alpha-fetoprotein promoter,    and a COX-2 promoter.-   [18]. The adenoviral genome according to any of [1] to [17], wherein    the adenovirus is an oncolytic adenovirus.-   [19]. The adenoviral genome according to [18], wherein said    adenoviral genome further comprises mutations in one or more genes    selected from the group consisting of E1a, E1b, E4, and VA-RNAs, to    achieve selective replication in tumours.-   [20]. The adenoviral genome according to any of [1] to [19], wherein    the adenoviral genome further comprises capsid modifications to    increase adenovirus infectivity or to target it to a receptor    present in a tumour cell.-   [21]. The adenoviral genome according to [20], wherein the    modification of the capsid is the insertion of an RGD motif into the    H1 loop of the adenoviral fiber protein.-   [22]. The adenoviral genome according to any of [1] to [21], wherein    the adenoviral genome comprises one or more further genes inserted    in said genome.-   [23]. The adenoviral genome according to [22], wherein the further    genes are one or more non-adenoviral genes used in gene therapy or    in vaccination.-   [24]. The adenoviral genome according to [23], wherein said genes    are genes used in cancer gene therapy.-   [25]. The adenoviral genome according to [24], wherein said genes    used in cancer gene therapy are at least a gene selected from the    group consisting of prodrug-activating genes, tumour-suppressor    genes, genes encoding anti-tumour interfering RNAs and    immunostimulatory genes.-   [26]. A recombinant adenovirus having an adenoviral genome according    to any of [1] to [25].-   [27]. A pharmaceutical composition comprising a therapeutically    effective amount of a recombinant adenovirus according to [26]    together with a pharmaceutically acceptable carrier.-   [28]. A recombinant adenovirus according to [26] or a pharmaceutical    composition according to [27] for use in medicine.-   [29]. A recombinant adenovirus according to [26] or a pharmaceutical    composition according to [27] for use in the prevention and/or    treatment of cancer in a mammal, wherein the adenovirus is an    oncolytic adenovirus or an adenovirus having an adenoviral genome    according to [24] or [25].-   [30]. The recombinant adenovirus for use according to [28] or [29],    wherein the mammal is a human being.-   [31]. The recombinant adenovirus for use according to [28], [29] or    [30], wherein the adenovirus is systemically administered.

The following examples are provided as merely illustratives and are notto be construed as limiting the scope of the invention.

EXAMPLES

Materials and Methods

Cell lines. HEK293 (human embryonic kidney), A549 (human lungadenocarcinoma), Sk-mel28 (melanoma), and MCF7 (human breastadenocarcinoma) cells were obtained from the American Type CultureCollection (ATCC, Manassas, Va.). All tumour cell lines, excluding MCF7,were maintained with Dulbecco's Modified Eagle's Medium supplementedwith 5% fetal bovine serum at 37° C., 5% CO₂. MCF7 cells were maintainedwith RPMI 1640 medium supplemented with 10% fetal bovine serum. All celllines were routinely tested for mycoplasma presence.

Viruses construction. ICOVIR15 oncolytic adenovirus has been previouslydescribed (Rojas J J, et al. Minimal RB-responsive E1A promotermodification to attain potency, selectivity, and transgene-armingcapacity in oncolytic adenoviruses. Mol Ther 2010; 18 (11):1960-71).AdGL is a E1-deleted first generation vector expressing theEGFP-Luciferase fusion protein cassette from pEGFPLuc (Clontech).Insertion of the CMV promoter −EGFPLuc-polyA cassette replacing the E1region was performed following a recombineering protocol adapted fromStanton et al. (Stanton R J, et al. Re-engineering adenovirus vectorsystems to enable high-throughput analyses of gene function.Biotechniques 2008; 45(6):659-62, 664-8) based on homologousrecombination in bacteria using a positive-negative selection. TheCMV-GFPLuc cassette flanked with E1 homologous regions was used toreplace the positive-negative selection markers of pAd5-CV5-E3+,commonly used to construct E1-deleted adenovirus vectors. ICOVIR15 waspropagated in A549 cells and the replication-deficient AdGL waspropagated in HEK293 cells.

ICOVIR15-ABD and AdGL-ABD were constructed by inserting theAlbumin-binding domain (ABD) flanked by two linkers (GSGS) (SEQ ID NO:2) in the hyper-variable region 1 (HVR1) of the adenovirus hexon afterthe D150 amino acid. The nucleotide sequence of the complete modifiedhexon having ABD inserted in HVR1 (ABD-HVR1) is SEQ ID NO: 3. Allmodifications were performed following a recombineering protocol adaptedfrom Stanton et al. (Stanton R J, et al. Re-engineering adenovirusvector systems to enable high-throughput analyses of gene function.Biotechniques 2008; 45(6):659-62, 664-8) based on homologousrecombination in bacteria using a positive-negative selection with theRpsL-Neo cassette.

First, the rpsLNeo cassette was amplified by PCR from pJetRpsLNeo, aplasmid containing the rpsLneo positive-negative selection markerscloned into pJet1.2/blunt (Genscript, Wheelock House, Hong Kong), usingoligonucleotides HVR1rpsLF5′-GCCCTGGCTCCCAAGGGTGCCCCAAATCCTTGCGAATGGGGCCTGGTGATGATGGC-3′ (SEQ IDNO: 12) and HVR1rpsLR5′-GTAATATTTATACCAGAATAAGGCGCCTGCCCAAATACGTGAGTTCAGAAGAACTCGTCAAGAAG-3′(SEQ ID NO: 13). The cassette was inserted in the HVR1 of pAdZICOVIR15and pAdZGL plasmids creating pAdZICOVIR15-H1-rpsLNeo andpAdZGL-H1-rpsLNeo. Second, the Linker-ABD-Linker fragment was generatedby PCR using the following overlapping oligonucleotides:

Oligo- SEQ ID nucleotide Sequence NO: ABDH1F5′-CCCAAGGGTGCCCCAAATCCTTGCGAATGGGATGAAGCTGCTAC 14TGCTCTTGAAATAAACCTAGAAGAAGAGGACGGCAGCGGATCCCTG-3′ ABDR15′-CCCGGTTCGCAAGCACCTTAGCCTCGGCCAGGGATCCGCTGCCC 15 CATTC-3 ABDF25′-GCTTGCGAACCGGGAACTAGACAAATACGGTGTTTCTGATTATT 16 ACAAG-3 ABDR25′-CGACGGTTTTGGCATTGTTAATCAAATTCTTGTAATAATCAGAA 17 ACACCG-3′ ABDF35′-ATGCCAAAACCGTCGAGGGCGTAAAGGCTCTGATCGACGAAATA 18 CTTGCG-3′ ABDR35′-ATACGTGAGTGCTACCAGACCCGGGTAGGGCCGCAAGTATTTCG 19 TCGATC-3′ ABDH1R5′-CAGAATAAGGCGCCTGCCCAAATACGTGAGTTTTTTGCTGCTCA 20GCTTGCTCGTCTACTTCGTCTTCGTTGTCATCGCTACCAGACCCGGG-3′

This fragment was used to replace the rpsLNeo cassette in both plasmidscreating pAdZICOVIR15-H1-ABD and pAdZGL-H1-ABD.

Also, the ABD was inserted in the hyper-variable region 5 of AdGL afterthe A274 aminoacid. The nucleotide sequence of the complete modifiedhexon having ABD inserted in HVR5 (ABD-HVR5) is SEQ ID NO: 4. For thispurpose, the rpsLNeo cassette was amplified by PCR from pJetRpsLNeousing oligonucleotides H5rpsLF and H5rpsLR as follows

Oligo- SEQ ID nucleotide Sequence NO: H5rpsLF5′-gaaagctagaaagtcaagtggaaatgcaa 21 tttttctcaactggcctggtgatgatggc-3′H5rpsLR 5′-gtttctatatctacatcttcactgtacaa 22taccactttaggtcagaagaactcgtcaagaa g-3′and inserted in pAdZGL plasmid, creating the pAdZGL-H5-rpsLNeo. In asecond recombination step, the Linker-ABD-Linker fragment was amplifiedby PCR from pAdZICOVIR15-H1-ABD using oligonucleotides ABDHSF and ABDHSRas follows:

Oligo- SEQ ID nucleotide Sequence NO: ABDH5F 5′- 23ctggccgaggctaaggtgcttgcgaaccgggaactagacaaatacggtgtttctgattattacaagaatttgattaacaatgccaaaaccgtcgagggcgtaaaggctctgatcgacgaaatacttgcggccctaccc-3′ ABDH5R 5′- 24ctggccgaggctaaggtgcttgcgaaccgggaactagacaaatacggtgtttctgattattacaagaatttgattaacaatgccaaaaccgtcgagggcgtaaaggctctgatcgacgaaatacttgcggccctaccc-3′

This fragment was used to replace the rpsLNeo of pAdZGL-H5-rpsLNeocreating the pAdZGL-H5-ABD.

Additionally, the domain could also be inserted in any of thehypervariable regions of the hexon protein. To do so, the rpsLNeo shouldbe inserted in the desired region and then replaced by the ABD fragmentgenerated by PCR with homology arms to recombine in the specifichypervariable loop.

ICOVIR15-ABD (ABD in HVR1), AdGL-ABD (ABD in HVR1), and AdGL-H5-ABD (ABDin HVR5) were generated by transfection of the generated plasmids withcalcium phosphate standard protocol in HEK293 cells. Oncolyticadenovirus ICOVIR15-ABD was plaque-purified and further amplified inA549 cells. Adenoviral vector AdGL-ABD was plaque-purified and furtheramplified in HEK293 cells. Both viruses were purified using a cesiumchloride double-gradient according to standard techniques.

Incubation of viruses with human serum albumin (HSA) was performed forone hour at room temperature with medium containing 1 mg/ml of HSA.

Viral production assay. A549 cells were infected with 800 viralparticles (vp) per cell of each virus to obtain a 80-100% of infection.Cells were washed thrice with PBS 4 hours after the infection andincubated with fresh medium. At the indicated time points, cells werecollected and frozen-thawed three times to obtain the cell extract.Viral titers were obtained by an antihexon staining-based method(Cascallo M, et al. Systemic toxicity-efficacy profile of ICOVIR-5, apotent and selective oncolytic adenovirus based on the pRB pathway. MolTher 2007; 15:1607-15) in HEK293 cells.

In vitro cytotoxicity assays. Cytotoxicity assays were performed byseeding 10,000 HEK293, 30,000 A549, 10,000 Sk-mel28 and 20,000 MCF-7cells per well in 96-well plates. Prior to the infection, viruses wereincubated for one hour at room temperature with either medium or mediumcontaining 1 mg/ml of human serum albumin (HSA). Cells were infected innormal medium or in albumin-containing medium with serial dilutions (⅓for HEK293, Sk-mel28 and MCF-7 cells, and ⅕ for A549 cells) startingwith 10,000 vp/cell. At day 7 post-infection plates were washed with PBSand stained for total protein content (bicinchoninic acid assay; PierceBiotechnology, Rockford, Ill.) and absorbance was quantified. The vp percell required to produce 50% growth inhibition (IC₅₀) was determinedfrom dose-response curves by standard nonlinear regression (GraFit;Erithacus Software, Horley, UK), using an adapted Hill equation.

Detection of binding to Human and Mouse Serum Albumin. Detection ofbinding to human serum albumin (HSA) and mouse serum albumin (MSA) wasperformed following an ELISA protocol adapted from Konig and Skerra(Konig T, Skerra A. Use of an albumin-binding domain for the selectiveimmobilisation of recombinant capture antibody fragments on ELISAplates. J Immunol Methods 1998; 218:73-83). Incubations were performed 1h at room temperature followed by three washing steps with 200 μl of PBScontaining 0.1% Tween20, which was also the buffer used to diluteviruses and antibodies.

The 96-well plate was coated with 200 μl of either HSA or BSA (Sigma) at2 mg/mL diluted in PBS. Remaining binding sites on the plastic surfacewere blocked with 2 mg/mL of BSA diluted in PBS containing 0.5% Tween20.In the next step, the purified viruses were added in a volume of 50 μl.Three different amounts of viral protein were tested to detect thebinding (25, 2.5, and 0.25 ng of viral protein) (FIG. 5A). Viral proteinconcentration of the purified virus samples was quantified using Bio RadProtein assay. Detection of viruses was performed with antihexonantibody from 2Hx-2 hybridoma (ATCC® HB-8117™) supernatant (50 μl perwell at a dilution of ⅕) and a polyclonal goat anti-mouse conjugatedwith horseradish peroxidase (50 μl per well at a dilution of 1/2000).Wells were stained adding 100 μl per well of freshly mixed3,3′,5,5′-tetramethylbenzidine peroxidase substrate solution andincubated 15 min with shaking. The reaction was stopped adding 100 μl ofsulphuric acid 2N and the absorbance was measured at 450 nm.

The same experiment was carried out coating a 96-well plate with 200 μlof either BSA, HSA or MSA (Sigma) at 2 mg/mL diluted in PBS and testing25 ng of viral protein to detect the binding. A control mock groupwithout virus was included (FIG. 5B).

In vitro antibody-mediated neutralization assays. Antibody-mediatedneutralization was analysed at the level of infection (transduction withluciferase-GFP reporter adenoviruses) and replication (cytotoxicitymediated by replication-competent adenoviruses). The commercial antibodyAb6982 (Anti-Ad5 rabbit polyclonal, Abcam) was used as a neutralizingantibody. For the infectivity analysis, starting from a 1/100 dilutionof the antibody stock, serial dilutions ⅙ of the antibody were performedin medium containing the different adenoviruses (AdGL or AdGL-ABD) in96-well plates.

After one hour of incubation at room temperature, 1E5 HEK293 or 3E4Sk-mel28 cells per well were added to obtain the desired multiplicity ofinfection (0.5 TU/cell or 10 vp/cell for HEK293 cells and 40 vp/cell forSk-mel28 cells). Twenty-four hours after the infection, medium wasremoved and cells were lysed adding 50 μl of Cell Lysis reagent(Promega, Madison, Wis.) and frozen-thawed once. Lysates werecentrifuged at 13,000 g for 5 minutes at 4° C. and the luciferase enzymeactivity of the supernatant was measured using Luciferase Assay Reagent(Promega) in a luminometer (Berthold Junior, Berthold GmbH&Co, KG,Germany).

For the analysis of replication, a serial dilution ½ of the antibody wasperformed starting from a 1/100 dilution of the antibody stock. Thisserial dilution was performed using medium containing ICOVIR15 orICOVIR15-ABD. One hour after incubation with the antibody at roomtemperature, 3E5 A549 cells per well were added to obtain a multiplicityof infection of 600 vp/cell. At day 4 post-infection cell viability wasanalyzed by staining the total protein content as described above in “invitro cytotoxicity assays” material and methods section.

In vivo blood clearance. In vivo studies were performed at theICO-IDIBELL facility (Barcelona, Spain) AAALAC unit 1155, and approvedby IDIBELL's Ethical Committee for Animal Experimentation. Balb/C nu/nufemale mice were injected intravenously with a mixture of ICOVIR15 andICOVIR15-ABD (ratio 1:1) with a total dose of 5×10¹⁰ vp in a volume of10 ml/kg in PBS (n=5). At 5 min, 15 min, 1 h, 4 h, and 24 hpost-administration, blood samples were collected from the tail vein.Blood samples were centrifuged at 5000 g for 5 minutes at 4° C. toseparate the cell fraction and collect the serum. Serum samples weredigested with proteinase K and SDS for 45 minutes at 54° C. and laterfor 10 minutes at 90° C. to proteolyze the capsid and release the viralDNA. Digested samples were amplified by PCR using hexon HVR1-flankingoligonucleotides Ad19121F 5′-CTGGACATGGCTTCCACGTA-3′ (SEQ ID NO: 25) andAd19300R 5′-GCTCGTCTACTTCGTCTTCG-3′ (SEQ ID NO: 26), and analysed byelectrophoresis on a 1% agarose gel. As ICOVIR15-ABD has the insertionof ABD in the middle of HVR1, the size of the PCR product will belonger: the PCR product expected from ICOVIR15-ABD is 361 bp compared to199 bp from ICOVIR15.

In vivo antitumoural efficacy. Subcutaneous melanoma xenograft tumourswere established by injection of 1×10⁷ Sk-mel28 cells into the flanks of6-week-old female Balb/C nu/nu mice. When tumours reached 150 mm³(experimental day 0), mice were randomized (n=10 to 12 animals pergroup) and were injected with a single intravenous administration of PBSor 5×10¹⁰ vp of ICOVIR15 or ICOVIR15-ABD in a volume of 10 ml/kg in PBSvia tail vein. Tumour size and mice status were monitored thrice perweek. Tumour volume was measured with a digital calliper and defined bythe equation V(mm³)=π/6×W²×L, where W and L are the width and the lengthof the tumour, respectively. The statistical significance of differencesin tumour size between treatment groups was assessed by a two-tailedStudent's unpaired t-test.

In vivo transduction. Melanoma tumors were established implanting 1×10⁶B16-CAR cells subcutaneously into both flanks of 6-week-old femaleC57BL6 mice (n=4-6 animals per group). When tumors reached 100 mm³, micewere injected intraperitoneally with either PBS (naïve group) or with2×10¹⁰ vp of hAd5wt (preimmunized group). Seven days after-immunization,animals were injected with a single intravenous administration of PBS,AdGL, or AdGL-ABD at a dose of 3×10¹⁰ viral particles per mouse. Threedays after vector injection mice received an intraperitoneal injectionof 250 μL of D-Luciferin (15 mg/mL; Biosynth, Staad, Switzerland) andmice were sacrificed for liver and tumor harvesting for bioluminescentimaging (IVIS). Organs were imaged on the IVIS Lumina XR (Caliper LifeSciences, Hopkinton, Mass.) and the Living Image v4.0 software was usedto quantify the emission of light.

Results

Generation and characterization of ICOVIR15-ABD. To generate analbumin-binding adenovirus, the albumin-binding domain 3 from theprotein G of streptococcus bacteria (SEQ ID NO: 1) was inserted in theHVR1 of ICOVIR15 hexon, generating the oncolytic adenovirus ICOVIR15-ABD(FIGS. 1 and 2 ). The domain was inserted flanked by two linkers (GSGS)(SEQ ID NO: 2) in the middle of the HVR1 after the D150 amino acidwithout deleting any hexon sequence (FIG. 1 ).

To analyze the impact of the ABD insertion on virus replication, wecompared the replication kinetics of ICOVIR15 and ICOVIR15-ABD in A549cells. As shown in FIG. 3 , even though the kinetics of production ofboth viruses were similar, a reduction in the total production yield ofICOVIR15-ABD was observed. Virus ability to kill cancer cells in vitrowas also analyzed. Cytotoxicity experiments were performed in HEK293,A549, Sk-mel28 and MCF-7 cells, in presence or absence of HSA. IC₅₀values indicated no significant differences among viruses in three outof four cell lines tested, and a 3-fold IC₅₀ increase for ICOVIR15-ABDcompared to ICOVIR15 in MCF-7 cells, indicating a certain loss ofcytotoxicity in this cell line (FIG. 4 ). Addition of HSA did not affectthe cytotoxicity in any case.

An ELISA experiment was performed to demonstrate binding of ICOVIR15-ABDto HSA and MSA. Wells were coated with either MSA, HSA or BSA (note thatABD binds to MSA and HSA, but not to BSA) and binding of both virusesICOVIR15 or ICOVIR15-ABD was analyzed. Positive signal was obtained whenadding ICOVIR15-ABD to both HSA-coated wells (FIG. 5A) and MSA-coatedwells (FIG. 5B) and the intensity of the signal increased with theamount of virus used (FIG. 5A). When BSA was used instead of HSA or MSA,no signal was observed regardless of the amount of virus added,indicating that the virus can bind to human and murine but not to bovinealbumin. As expected, no binding was detected with ICOVIR15 virus in anycase.

Albumin-binding protects adenovirus from neutralizing antibodies invitro. Having demonstrated the binding of ICOVIR15-ABD to human albumin,the inventors tested if this binding could protect the virus fromneutralizing antibodies (NAbs) in vitro. For this, an adenovirus vectorexpressing a GFP-Luciferase fusion protein modified with ABD at thehexon, named AdGL-ABD, was constructed. The transduction efficiency ofAdGL-ABD in HEK293 cells was studied, after incubation with serialdilutions of the commercial neutralizing antibody Ab6982 (rabbitpolyclonal antibody against Ad5) in presence and absence of HSA. Asshown in FIG. 6 , similar levels of transduction were achieved with thenon modified AdGL vector regardless of albumin incubation. In contrast,HSA protected AdGL-ABD from neutralization. Interestingly, the AdGL-ABDwas less neutralized than the non-modified vector AdGL even when notincubated with albumin, indicating that the mere modification of theHVR1 with the ABD already precluded binding of some NAbs.

In addition, the capacity of viruses to kill cancer cells in presence ofneutralizing antibodies was also analyzed. For this purpose, A549 cellswere infected with ICOVIR15 or ICOVIR15-ABD previously incubated withserial dilutions of the neutralizing antibody Ab6982 in presence andabsence of HSA, and cell survival was analyzed 4 days after theinfection. In absence of human albumin both viruses showed similarcapacity to kill tumor cells (FIG. 7 ), and only a small increase ofcytotoxicity was observed with ICOVIR15-ABD probably due to the certainevasion of neutralizing antibodies observed in transduction (FIG. 6 ).Importantly, when human albumin was added to the media the cytotoxicityof ICOVIR15-ABD was significantly enhanced in contrast to that ofICOVIR15 which remained unaltered.

ICOVIR15-ABD displays an increased plasma half life. To investigatewhether albumin-binding can reduce the rapid blood clearance ofadenovirus, the pharmacokinetics of ICOVIR15-ABD after systemicadministration in vivo was studied. Mice were injected with a mixture ofICOVIR15 and ICOVIR15-ABD at a ratio 1:1 with a total dose of 5×10¹⁰viral particles per mouse, and blood samples were collected at differenttime points. Amplification of hexon HVR1 was performed by PCR in serumsamples. Because of the ABD insertion, a 361 bp band is obtained withICOVIR15-ABD whereas with ICOVIR15 the size of the band is only 199 bp.Hence, comparing the relative intensity of the bands at each time pointit was possible to determine which virus persists longer in thebloodstream. FIG. 8 shows the electrophoresis of the PCR reactions ofall samples including a standard with several ratios of ICOVIR15-ABD:ICOVIR15 (0.2, 1, 5, 10 and 50), the pre-injection control, and thewater negative control. Equally intense bands were obtained in thepre-injection control and 5 minutes after the injection. From then on, ashift on the intensity of the bands can be seen as the bandcorresponding to ICOVIR15-ABD becomes more intense than the ICOVIR15one. At 1 h after the injection the differential persistence of bothviruses is clearly evident in favour of ICOVIR15-ABD. These dataindicate that after 5 minutes post-injection ICOVIR15 is cleared fromthe bloodstream much quicker than ICOVIR15-ABD, demonstrating theimproved pharmacokinetics of the ABD-modified virus.

Anti-tumour activity of ICOVIR15-ABD after systemic administration invivo. Once demonstrated the increased plasma half-life of ICOVIR15-ABD,it was tested whether this translated in an increased anti-tumourefficacy after systemic administration. Mice bearing Sk-mel28 (melanoma)xenograft tumours were injected with a single intravenous dose ofphosphate-buffered saline (PBS), ICOVIR15 or ICOVIR15-ABD at 5×10¹⁰viral particles per mouse. At day 38 after treatment, animals weresacrificed due to the large size of PBS-treated tumours. Both viruseswere able to significantly reduce the tumour growth compared with PBS(FIG. 9 ). However, ICOVIR15-ABD treatment showed a statisticalreduction in tumour growth from day 21 until the end of treatment,whereas ICOVIR15 could not statistically control tumour growth until day35. At day 38 when animals were sacrificed, ICOVIR15 induced a reductionof 1.4-fold compared to a 2-fold reduction with ICOVIR15-ABD.

Albumin-binding protects adenovirus from anti-HAd5 preimmunity in vivo.Immunocompetent C57BL6 mice bearing B16-CAR melanoma tumors wereimmunized with an intraperitoneal injection of 2×10¹⁰ viral particles ofhAd5wt or with PBS (preimmunized or naïve groups). Seven days later,mice received a single intravenous dose of PBS, AdGL, or AdGL-ABD at3×10¹⁰ viral particles per mouse. Three days after vector injection micewere sacrificed and liver and tumors were harvested for in vivobioluminescent imaging (IVIS). No significant differences were observedamong vectors in liver and tumor transduction in naïve animals (FIG. 10). Of note, when animals were preimmunized the non-modified AdGL vectorsuffered a complete neutralization as the transduction of liver andtumors was completely abolished. On the contrary, AdGL-ABD is able tomaintain the same levels of transduction in liver and tumors, indicatinga protection from anti-HAd5 preimmunity.

Insertion of ABD in hypervariable region 5. To test whether thisinsertion could also be made in other hypervariable regions of the hexonwe constructed the AdGL-H5-ABD vector. HEK293 cells were transfectedwith pAdZGL-H5-ABD plasmid to generate AdGL-H5-ABD virus. One week aftertransfection the cells and supernatant were harvested and lysed by threefreeze-thaw cycles. The cell extract containing virus was tittered inHEK293 cells by plaque assay. Wells corresponding to dilutions 1E6, 1E7and 1E8 are shown in FIG. 11 , where plaques demonstrating viruspropagation are evident. Insertion of ABD in HVR5 was confirmed bysequencing the virus genome. This demonstrates the possibility ofinserting the ABD in other hypervariable regions without affecting theviability of the virus.

Insertion of ABD in hypervariable region 5 does not protect adenovirusfrom neutralizing antibodies. To check if the ABD inserted in thehypervariable region 5 could also protect adenovirus from neutralizingantibodies, we compared the transduction efficiency of the vectors AdGL,AdGL-H1-ABD and AdGL-H5-ABD after incubation with serial dilutions ofthe Ab6982 NAb with or without HSA in HEK293 and Sk-mel28 cells. Asobserved in FIG. 6 , incubation with HSA provided a clear advantage oftransduction to AdGL-H1-ABD in both cell lines, whereas it had noimportant effect on the non-modified vector AdGL (FIG. 12 ).Surprisingly, addition of human albumin did not increase thetransduction levels of AdGL-H5-ABD. This indicates that the ABD isfunctional when inserted in HVR1 but not in HVR5.

What is claimed is:
 1. A recombinant oncolytic adenovirus comprising apolynucleotide encoding a hexon protein comprising an albumin-bindingmoiety inserted within its hypervariable region 1 (HVR1), wherein theoncolytic adenovirus is human adenovirus serotype
 5. 2. The recombinantoncolytic adenovirus according to claim 1, wherein the albumin-bindingmoiety is selected from an albumin-binding domain from streptococcalprotein G, an albumin-binding domain from Peptostreptococcus magnusprotein PAB, an albumin-binding peptide having the core sequenceDICLPRWGCLW (SEQ ID NO: 9), and functionally equivalent variantsthereof.
 3. The recombinant oncolytic adenovirus according to claim 2,wherein the albumin-binding moiety is the albumin-binding domain 3 fromstreptococcal protein G.
 4. The recombinant oncolytic adenovirusaccording to claim 1, wherein the hexon protein contains thealbumin-binding moiety inserted after amino acid residue D150 of thehexon protein according to the numbering of the hexon protein of SEQ IDNO:
 27. 5. The recombinant oncolytic adenovirus according to claim 1,wherein the N- and/or the C-terminus of the albumin-binding moiety isconnected to the hexon protein by a linker sequence.
 6. The recombinantoncolytic adenovirus according to claim 5, wherein said linker sequencecomprises the sequence GSGS (SEQ ID NO: 2).
 7. The recombinant oncolyticadenovirus according to claim 1, wherein said oncolytic adenovirusfurther comprises a polynucleotide encoding a tissue-specific promoteror a tumour-specific promoter.
 8. The recombinant oncolytic adenovirusaccording to claim 1, wherein said oncolytic adenovirus furthercomprises mutations in one or more genes selected from E1a, E1b, E4, andVA-RNAs.
 9. The recombinant oncolytic adenovirus according to claim 1,wherein the oncolytic adenovirus further comprises one or more capsidmodifications to increase oncolytic adenovirus infectivity and/or totarget the oncolytic adenovirus to a receptor present in a tumour cell.10. The recombinant oncolytic adenovirus according to claim 9, whereinthe one or more capsid modifications comprise insertion of an RGD motifinto the H1 loop of the adenoviral fiber protein.
 11. The recombinantoncolytic adenovirus according to claim 9 wherein the one or more capsidmodifications comprise substitution of a region of the fiber gene withthe homologous region from a different adenovirus serotype to form achimeric adenovirus.
 12. The recombinant oncolytic adenovirus accordingto claim 1, wherein the oncolytic adenovirus comprises one or morepolynucleotides encoding one or more non-adenoviral genes and said genesare genes used in gene therapy or in vaccination.
 13. The recombinantoncolytic adenovirus according to claim 12, wherein said genes are genesused in cancer gene therapy.
 14. A pharmaceutical composition comprisinga therapeutically effective amount of a recombinant oncolytic adenovirusaccording to claim 1 together with a pharmaceutically acceptablecarrier.
 15. A method for the treatment of cancer in a mammal comprisingadministering to said mammal a recombinant oncolytic adenovirusaccording to claim 1, wherein the oncolytic adenovirus comprises anoncolytic adenovirus comprising one or more polynucleotides encoding oneor more non-adenoviral genes used in cancer gene therapy.
 16. The methodaccording to claim 15, wherein the oncolytic adenovirus is systemicallyadministered.